label OpenAPI auto-generated PRs (#16723)

.github/workflows/openapi-decorate.yml

@@ -10,6 +10,11 @@ jobs:
     if: github.event.pull_request.user.login == 'github-openapi-bot'
     runs-on: ubuntu-latest
     steps:
+      - name: Label pull requests with 'github-openapi-bot'
+        uses: rachmari/labeler@832d42ec5523f3c6d46e8168de71cd54363e3e2e
+        with:
+          repo-token: '${{ secrets.GITHUB_TOKEN }}'
+          add-labels: 'github-openapi-bot'
       - name: Checkout repository code
         uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f