test: add change in backend/pyproject

.github/workflows/pdm-lock-automation.yaml

@@ -86,6 +86,7 @@ jobs:
           pre-commit run pdm-lock-check
           echo "checking changes for $file_path for self branch before commit"
           echo "changed=false" >> $GITHUB_OUTPUT
+          git fetch origin
           if git diff --quiet -- "$file_path"; then
             echo "No changes detected in $file_path against self branch."
           else