prepare to rename default branch to main

- update references to default branch name in docs, workflows
- use HEAD in github urls, which always works regardless of default branch name
- fix petstore URLs since the old petstore links seem to have stopped working

docs/source/api/index.rst

@@ -18,7 +18,7 @@ information on:
 - learning more about JupyterHub's API
 
 The same JupyterHub API spec, as found here, is available in an interactive form
-`here (on swagger's petstore) <http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default>`__.
+`here (on swagger's petstore) <https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/HEAD/docs/rest-api.yml#!/default>`__.
 The `OpenAPI Initiative`_ (fka Swagger™) is a project used to describe
 and document RESTful APIs.
 

docs/source/contributing/docs.rst

@@ -13,7 +13,7 @@ Building documentation locally
 We use `sphinx <http://sphinx-doc.org>`_ to build our documentation. It takes
 our documentation source files (written in `markdown
 <https://daringfireball.net/projects/markdown/>`_ or `reStructuredText
-<http://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_ &
+<https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_ &
 stored under the ``docs/source`` directory) and converts it into various
 formats for people to read. To make sure the documentation you write or
 change renders correctly, it is good practice to test it locally.
@@ -39,8 +39,8 @@ change renders correctly, it is good practice to test it locally.
    along with the filename / line number in which they occurred. Fix them,
    and re-run the ``make html`` command to re-render the documentation.
 
-#. View the rendered documentation by opening ``build/html/index.html`` in 
-   a web browser. 
+#. View the rendered documentation by opening ``build/html/index.html`` in
+   a web browser.
 
    .. tip::
 

docs/source/contributing/index.rst

@@ -6,8 +6,8 @@ We want you to contribute to JupyterHub in ways that are most exciting
 & useful to you. We value documentation, testing, bug reporting & code equally,
 and are glad to have your contributions in whatever form you wish :)
 
-Our `Code of Conduct <https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md>`_
-(`reporting guidelines <https://github.com/jupyter/governance/blob/master/conduct/reporting_online.md>`_)
+Our `Code of Conduct <https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md>`_
+(`reporting guidelines <https://github.com/jupyter/governance/blob/HEAD/conduct/reporting_online.md>`_)
 helps keep our community welcoming to as many people as possible.
 
 .. toctree::

docs/source/gallery-jhub-deployments.md

@@ -30,7 +30,7 @@ Please submit pull requests to update information or to add new institutions or
 
 ### University of California Davis
 
-- [Spinning up multiple Jupyter Notebooks on AWS for a tutorial](https://github.com/mblmicdiv/course2017/blob/master/exercises/sourmash-setup.md)
+- [Spinning up multiple Jupyter Notebooks on AWS for a tutorial](https://github.com/mblmicdiv/course2017/blob/HEAD/exercises/sourmash-setup.md)
 
 Although not technically a JupyterHub deployment, this tutorial setup
 may be helpful to others in the Jupyter community.

docs/source/index.rst

@@ -115,8 +115,8 @@ We want you to contribute to JupyterHub in ways that are most exciting
 & useful to you. We value documentation, testing, bug reporting & code equally,
 and are glad to have your contributions in whatever form you wish :)
 
-Our `Code of Conduct <https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md>`_
-(`reporting guidelines <https://github.com/jupyter/governance/blob/master/conduct/reporting_online.md>`_)
+Our `Code of Conduct <https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md>`_
+(`reporting guidelines <https://github.com/jupyter/governance/blob/HEAD/conduct/reporting_online.md>`_)
 helps keep our community welcoming to as many people as possible.
 
 .. toctree::
@@ -147,4 +147,4 @@ Questions? Suggestions?
 
 .. _JupyterHub: https://github.com/jupyterhub/jupyterhub
 .. _Jupyter notebook: https://jupyter-notebook.readthedocs.io/en/latest/
-.. _REST API: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default
+.. _REST API: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/HEAD/docs/rest-api.yml#!/default

docs/source/installation-guide-hard.rst

@@ -3,4 +3,4 @@
 JupyterHub the hard way
 =======================
 
-This guide has moved to https://github.com/jupyterhub/jupyterhub-the-hard-way/blob/master/docs/installation-guide-hard.md
+This guide has moved to https://github.com/jupyterhub/jupyterhub-the-hard-way/blob/HEAD/docs/installation-guide-hard.md

docs/source/reference/authenticators.md

@@ -259,7 +259,7 @@ PAM session.
 
 Beginning with version 0.8, JupyterHub is an OAuth provider.
 
-[authenticator]: https://github.com/jupyterhub/jupyterhub/blob/master/jupyterhub/auth.py
+[authenticator]: https://github.com/jupyterhub/jupyterhub/blob/HEAD/jupyterhub/auth.py
 [pam]: https://en.wikipedia.org/wiki/Pluggable_authentication_module
 [oauth]: https://en.wikipedia.org/wiki/OAuth
 [github oauth]: https://developer.github.com/v3/oauth/

docs/source/reference/rest.md

@@ -230,7 +230,7 @@ be viewed in a more [interactive style on swagger's petstore][].
 Both resources contain the same information and differ only in its display.
 Note: The Swagger specification is being renamed the [OpenAPI Initiative][].
 
-[interactive style on swagger's petstore]: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default
+[interactive style on swagger's petstore]: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/HEAD/docs/rest-api.yml#!/default
 [openapi initiative]: https://www.openapis.org/
 [jupyterhub rest api]: ./rest-api
-[jupyter notebook rest api]: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyter/notebook/master/notebook/services/api/api.yaml
+[jupyter notebook rest api]: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyter/notebook/HEAD/notebook/services/api/api.yaml

docs/source/reference/services.md

@@ -230,7 +230,7 @@ configurable by the `cookie_cache_max_age` setting (default: five minutes).
 For example, you have a Flask service that returns information about a user.
 JupyterHub's HubAuth class can be used to authenticate requests to the Flask
 service. See the `service-whoami-flask` example in the
-[JupyterHub GitHub repo](https://github.com/jupyterhub/jupyterhub/tree/master/examples/service-whoami-flask)
+[JupyterHub GitHub repo](https://github.com/jupyterhub/jupyterhub/tree/HEAD/examples/service-whoami-flask)
 for more details.
 
 ```python

docs/source/reference/spawners.md

@@ -125,7 +125,7 @@ If the `Spawner.options_form` is defined, when a user tries to start their serve
 
 If `Spawner.options_form` is undefined, the user's server is spawned directly, and no spawn page is rendered.
 
-See [this example](https://github.com/jupyterhub/jupyterhub/blob/master/examples/spawn-form/jupyterhub_config.py) for a form that allows custom CLI args for the local spawner.
+See [this example](https://github.com/jupyterhub/jupyterhub/blob/HEAD/examples/spawn-form/jupyterhub_config.py) for a form that allows custom CLI args for the local spawner.
 
 ### `Spawner.options_from_form`
 
@@ -166,7 +166,7 @@ which would return:
 
 When `Spawner.start` is called, this dictionary is accessible as `self.user_options`.
 
-[spawner]: https://github.com/jupyterhub/jupyterhub/blob/master/jupyterhub/spawner.py
+[spawner]: https://github.com/jupyterhub/jupyterhub/blob/HEAD/jupyterhub/spawner.py
 
 ## Writing a custom spawner
 

docs/source/reference/templates.md

@@ -10,7 +10,7 @@ appearance.
 
 JupyterHub will look for custom templates in all of the paths in the
 `JupyterHub.template_paths` configuration option, falling back on the
-[default templates](https://github.com/jupyterhub/jupyterhub/tree/master/share/jupyterhub/templates)
+[default templates](https://github.com/jupyterhub/jupyterhub/tree/HEAD/share/jupyterhub/templates)
 if no custom template with that name is found. This fallback
 behavior is new in version 0.9; previous versions searched only those paths
 explicitly included in `template_paths`. You may override as many
@@ -21,7 +21,7 @@ or as few templates as you desire.
 Jinja provides a mechanism to [extend templates](http://jinja.pocoo.org/docs/2.10/templates/#template-inheritance).
 A base template can define a `block`, and child templates can replace or
 supplement the material in the block. The
-[JupyterHub templates](https://github.com/jupyterhub/jupyterhub/tree/master/share/jupyterhub/templates)
+[JupyterHub templates](https://github.com/jupyterhub/jupyterhub/tree/HEAD/share/jupyterhub/templates)
 make extensive use of blocks, which allows you to customize parts of the
 interface easily.
 

docs/source/troubleshooting.md

@@ -234,7 +234,7 @@ With a docker container, pass in the environment variable with the run command:
       -e JUPYTERHUB_API_TOKEN=my_secret_token \
       jupyter/datascience-notebook:latest
 
-[This example](https://github.com/jupyterhub/jupyterhub/tree/master/examples/service-notebook/external) demonstrates how to combine the use of the `jupyterhub-singleuser` environment variables when launching a Notebook as an externally managed service.
+[This example](https://github.com/jupyterhub/jupyterhub/tree/HEAD/examples/service-notebook/external) demonstrates how to combine the use of the `jupyterhub-singleuser` environment variables when launching a Notebook as an externally managed service.
 
 ## How do I...?