fix: use newer buildx in workflows to get correct image digest for Helm chart app version (#17)

Author: alfredkrohmer

.github/workflows/publish.yaml

@@ -19,6 +19,9 @@ jobs:
     - name: Checkout repository
       uses: actions/checkout@v3
 
+    - name: Set up Docker Buildx (required due to bug in older version which populates image digest with a wrong value)
+      uses: docker/setup-buildx-action@4b4e9c3e2d4531116a6f8ba8e71fc6e2cb6e6c8c
+
     - name: Log in to the Container registry
       uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
       with: