remove releases to docker hub

.github/workflows/release.yml

@@ -9,6 +9,7 @@ on:
   push:
     branches:
       - main    # When `latest` image tag is published when default branch is updated
+      - use-docker-hub-as-test-registry    # for testing
     tags:
       - 'v*'    # When a tag starting with `v` is created e.g. v1.0.0
 
@@ -23,21 +24,13 @@ jobs:
     permissions:
       packages: write
       contents: read
-    environment: docker-hub    # Use `docker-hub` repository environment
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3    # https://github.com/marketplace/actions/docker-setup-build
 
-      - name: Log in to Docker Hub
-        uses: docker/login-action@v3    # https://github.com/marketplace/actions/docker-login
-        with:
-          registry: ${{ vars.DOCKER_REGISTRY_URL }}
-          username: ${{ secrets.DOCKER_REGISTRY_USERNAME }}
-          password: ${{ secrets.DOCKER_REGISTRY_PASSWORD }}
-
       - name: Log in to the Container registry
         uses: docker/login-action@v3    # https://github.com/marketplace/actions/docker-login
         with:
@@ -50,7 +43,6 @@ jobs:
         uses: docker/metadata-action@v5    # https://github.com/marketplace/actions/docker-metadata-action
         with:
           images: |
-            ${{ vars.DOCKER_REGISTRY_URL }}/${{ vars.DOCKER_REPOSITORY }}/${{ env.PROJECT }}
             ghcr.io/${{ github.repository }}
           tags: |
             # set latest tag for default branch