ci: Synchronize GitHub workflows with develop branch

.github/workflows/docker.yml

@@ -0,0 +1,74 @@
+name: Docker
+on:
+  pull_request:
+  push:
+    branches:
+      - 'develop'
+    tags:
+      - 'v?[0-9]+.[0-9]+.[0-9]+'
+env:
+  TEST_TAG: etherpad/etherpad:test
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Check out
+        uses: actions/checkout@v2
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      -
+        name: Build and export to Docker
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          load: true
+          tags: ${{ env.TEST_TAG }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+      -
+        name: Set up Node.js
+        uses: actions/setup-node@v3
+        with:
+          node-version: 'lts/*'
+          cache: 'npm'
+          cache-dependency-path: |
+            src/package-lock.json
+            src/bin/doc/package-lock.json
+      -
+        name: Test
+        run: |
+          docker run --rm -d -p 9001:9001 ${{ env.TEST_TAG }}
+          ./src/bin/installDeps.sh
+          sleep 3
+          (cd src && npm run test-container)
+          git clean -dxf .
+      -
+        name: Docker meta
+        if: github.event_name == 'push'
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: etherpad/etherpad
+          tags: |
+            type=ref,event=branch
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+      -
+        name: Log in to Docker Hub
+        if: github.event_name == 'push'
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      -
+        name: Build and push
+        if: github.event_name == 'push'
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}