chore: publish a Docker image (#8702)

This PR adds publishing of a Docker image to ghcr.io.

.github/workflows/publish.yml

@@ -5,6 +5,10 @@ on:
     tags:
       - v*
 
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
 jobs:
   publish:
     runs-on: ubuntu-latest
@@ -36,3 +40,25 @@ jobs:
           npm config set registry 'https://wombat-dressing-room.appspot.com/'
           npm config set '//wombat-dressing-room.appspot.com/:_authToken' '${NPM_TOKEN}'
           npm publish
+      # Based on https://docs.github.com/en/actions/publishing-packages/publishing-docker-images.
+      - name: Log in to the Container registry
+        uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@98669ae865ea3cffbcbaa878cf57c20bbf1c6c38
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+      - name: Pack Puppeteer for docker
+        run: docker/pack.sh
+      - name: Build and push the Docker image
+        uses: docker/build-push-action@ad44023a93711e3deb337508980b4b5e9bcdc5dc
+        working-directory: ./docker
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}