Fix updating swagger failure caused by no content to change

.gitea/workflows/update_swagger.yaml

@@ -11,11 +11,18 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - run: |
+          set -euo pipefail
+
           make update-api-docs
 
           git config --global user.name "Gitea Bot"
           git config --global user.email "teabot@gitea.io"
           git remote set-url origin https://x-access-token:${{ secrets.DEPLOY_TOKEN }}@gitea.com/gitea/docs.git
-          git add --all
-          git commit -m "[skip ci] Updated swagger files"
-          git push
+
+          if git status --porcelain | grep -q .; then
+            git add --all
+            git commit -m "[skip ci] Updated swagger files"
+            git push
+          else
+            echo "No API doc changes detected; skipping commit"
+          fi