fix: update image tag format in Docker build workflow (#17)

* fix: update image tag format in Docker build workflow

---------

On-behalf-of: @SAP angel.kafazov@sap.com
Signed-off-by: Angel Kafazov <akafazov@cst-bg.net>

Author: akafazov

.github/workflows/infra-helm-unittest.yml

@@ -33,4 +33,4 @@ jobs:
       with:
         context: infra/helm-unittest
         push: true
-        tags: ghcr.io/${{ github.repository }}/infra/helm-unittest:latest
+        tags: ghcr.io/platform-mesh/infra/helm-unittest:latest