.github/workflows: run chart test on PR (#137)

.github/workflows/push-chart.yaml

@@ -12,14 +12,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-name: Push Helm
+name: Helm
 on:
   push:
     branches:
       - master
+  pull_request:
+    branches:
+      - master
   workflow_dispatch:
 jobs:
   helm-test:
+    name: Test
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -43,7 +47,9 @@ jobs:
             exit 1
           fi
   helm-push:
+    name: Push to ghcr.io
     needs: [helm-test]
+    if: ${{ github.event_name == 'push' }}
     runs-on: ubuntu-latest
     defaults:
       run: