Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v3...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/release.yml

@@ -32,7 +32,7 @@ jobs:
   build-release:
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-python@v4
         with:
           python-version: "3.9"
@@ -103,7 +103,7 @@ jobs:
               echo "REGISTRY=localhost:5000/" >> $GITHUB_ENV
           fi
 
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       # Setup docker to build for multiple platforms, see:
       # https://github.com/docker/build-push-action/tree/v2.4.0#usage

.github/workflows/test-docs.yml

@@ -38,7 +38,7 @@ jobs:
   validate-rest-api-definition:
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Validate REST API definition
         uses: char0n/swagger-editor-validate@v1.3.2
@@ -48,7 +48,7 @@ jobs:
   test-docs:
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           # make rediraffecheckdiff requires git history to compare current
           # commit with the main branch and previous releases.

.github/workflows/test-jsx.yml

@@ -32,7 +32,7 @@ jobs:
     timeout-minutes: 5
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v3
         with:
           node-version: "14"

.github/workflows/test.yml

@@ -136,7 +136,7 @@ jobs:
           if [ "${{ matrix.jupyverse }}" != "" ]; then
               echo "JUPYTERHUB_SINGLEUSER_APP=jupyverse" >> $GITHUB_ENV
           fi
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       # NOTE: actions/setup-node@v3 make use of a cache within the GitHub base
       #       environment and setup in a fraction of a second.
       - name: Install Node v14
@@ -257,7 +257,7 @@ jobs:
     timeout-minutes: 20
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: build images
         run: |