Build the containers manifest for Dependabot Docker PRs

.github/workflows/dependabot-build.yml

@@ -16,6 +16,7 @@ jobs:
     # Map the step output to a job output for subsequent jobs
     outputs:
       dependency-type: ${{ steps.dependabot-metadata.outputs.dependency-type }}
+      package-ecosystem: ${{ steps.dependabot-metadata.outputs.package-ecosystem }}
     steps:
       - name: Fetch dependabot metadata
         id: dependabot-metadata
@@ -25,7 +26,8 @@ jobs:
   build-dependabot-changes:
     runs-on: ubuntu-latest
     needs: [fetch-dependabot-metadata]
-    if: ${{ needs.fetch-dependabot-metadata.outputs.dependency-type == 'direct:production' }}
+    # We only need to build the dist/ folder if the PR relates to Docker or a production NPM dependency, otherwise we don't expect changes.
+    if: needs.fetch-dependabot-metadata.output.package-ecosystem == 'docker' || ( needs.fetch-dependabot-metadata.output.package-ecosystem == 'npm_and_yarn' && needs.fetch-dependabot-metadata.outputs.dependency-type == 'direct:production' )
     steps:
       # Check out using a PAT so any pushed changes will trigger checkruns
       - uses: actions/checkout@v2
@@ -45,6 +47,14 @@ jobs:
       - name: Install NPM dependencies
         run: npm ci
 
+      # If we're reacting to a Docker PR, we have on extra step to refresh and check in the container manifest,
+      # this **must** happen before rebuilding dist/ so it uses the new version of the manifest
+      - name: Rebuild docker/containers.json
+        if: needs.fetch-dependabot-metadata.output.package-ecosystem == 'docker'
+        run: |
+          npm run update-container-manifest
+          git add docker/containers.json
+
       - name: Rebuild the dist/ directory
         run: npm run package