Inject default values to container image name to avoid CI failure in from-fork PRs (#108)

inject  default values so PR from forks will test building an image

Author: Oded-B

Diff for: .github/workflows/docker-publish.yml

@@ -75,7 +75,7 @@ jobs:
         uses: docker/metadata-action@906ecf0fc0a80f9110f79d9e6c04b1080f4a2621
         with: 
           images: |
-            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+            ${{ env.REGISTRY != '' && env.REGISTRY  || 'ghcr.io' }}/${{ env.IMAGE_NAME != '' && env.IMAGE_NAME || 'commercetools/telefonistka'}}
 
 
       # Build and push Docker image with Buildx (don't push on PR)
@@ -100,7 +100,7 @@ jobs:
         uses: docker/metadata-action@906ecf0fc0a80f9110f79d9e6c04b1080f4a2621
         with:
           images: |
-            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+            ${{ env.REGISTRY != '' && env.REGISTRY  || 'ghcr.io' }}/${{ env.IMAGE_NAME != '' && env.IMAGE_NAME || 'commercetools/telefonistka'}}
           flavor: prefix=alpine-,onlatest=true
 
       # Build and push Docker image with Buildx (don't push on PR)