actions: push container images to dockerhub

Author: Sameer Naik

.github/workflows/container.yaml

@@ -26,6 +26,13 @@ jobs:
         id: buildx
         uses: docker/setup-buildx-action@v2
 
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+        if: github.event_name != 'pull_request'
+
       - name: Login to GCR
         uses: docker/login-action@v2
         with:
@@ -38,7 +45,9 @@ jobs:
         id: meta
         uses: docker/metadata-action@v4
         with:
-          images: gcr.io/triggermesh/triggermesh-core
+          images: |
+            triggermesh/triggermesh-core
+            gcr.io/triggermesh/triggermesh-core
           tags: |
             type=semver,pattern={{raw}}
             type=sha