Update Docker image workflow to conditionally tag images with 'latest' for default branch

Author: tacxou

.github/workflows/docker-image.yml

@@ -36,7 +36,10 @@ jobs:
         id: metaDirector
         uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
         with:
-          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            # set latest tag for default branch
+            type=raw,value=latest,enable={{is_default_branch}}
 
       - name: Build and push Docker image (director)
         uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4
@@ -52,7 +55,10 @@ jobs:
         id: metaStorage
         uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
         with:
-          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            # set latest tag for default branch
+            type=raw,value=latest,enable={{is_default_branch}}
 
       - name: Build and push Docker image (storage)
         uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4
@@ -68,7 +74,10 @@ jobs:
         id: metaWebui
         uses: docker/metadata-action@9ec57ed1fcdbf14dcef7dfbe97b2010124a938b7
         with:
-          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            # set latest tag for default branch
+            type=raw,value=latest,enable={{is_default_branch}}
 
       - name: Build and push Docker image (webui)
         uses: docker/build-push-action@f2a1d5e99d037542a71f64918e516c093c6f3fc4