fix CI: tag for push not set

.github/workflows/publish.yml

@@ -26,13 +26,13 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
-      - name: Get the version
-        id: get_version
+      - name: Set the Docker image tag
+        id: set_docker_image_tag
         run: |
-          if [[ $GITHUB_REF == refs/pull/* ]]; then
-            echo "VERSION=$(git rev-parse --short HEAD)" >> $GITHUB_OUTPUT
-          elif [[ $GITHUB_REF == refs/tags/* ]]; then
-            echo "VERSION=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
+          if [[ $GITHUB_REF == refs/tags/* ]]; then
+            echo "TAG=${GITHUB_REF#refs/tags/}" >> $GITHUB_OUTPUT
+          else
+            echo "TAG=$(git rev-parse --short HEAD)" >> $GITHUB_OUTPUT
           fi
 
       - name: Build and push to Docker Hub
@@ -42,5 +42,5 @@ jobs:
           push: true
           file: ./ops/docker/op-stack-go/Dockerfile
           target: op-node-target
-          outputs: type=image,name=${{ vars.DOCKERHUB_REGISTRY_ID }}/op-node-babylon-finality-gadget:${{ steps.get_version.outputs.VERSION }}
+          outputs: type=image,name=${{ vars.DOCKERHUB_REGISTRY_ID }}/op-node-babylon-finality-gadget:${{ steps.set_docker_image_tag.outputs.TAG }}