Update hello_world.yml

.github/workflows/hello_world.yml

@@ -20,7 +20,10 @@ jobs:
     steps:
       - name: Validate tag
         run: |
-          [[ "${{ inputs.tag_name }}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]] && echo "tag name is ok"
+          if [[ ! "${{ inputs.tag_name }}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then 
+              echo "tag is invalid: must be in the form 'v0.0.0'"
+              exit 1
+          fi
       - name: Create tag
         uses: actions/github-script@v5
         with: