Login to GHCR in order to have access to private Docker images for e2e tests.

.github/workflows/build.yml

@@ -8,6 +8,7 @@ on: [push, pull_request]
 
 permissions:
   contents: read  # to fetch code (actions/checkout)
+  packages: read  # to fetch private images from GitHub Container Registry (GHCR)
 
 jobs:
   tests:
@@ -117,6 +118,14 @@ jobs:
           path: 'coverage/dspace-angular/lcov.info'
           retention-days: 14
 
+      # Login to our Docker registry, so that we can access private Docker images using "docker compose" below.
+      - name: Login to ${{ env.DOCKER_REGISTRY }}
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.DOCKER_REGISTRY }}
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       # Using "docker compose" start backend using CI configuration
       # and load assetstore from a cached copy
       - name: Start DSpace REST Backend via Docker (for e2e tests)