Update doxygen.yml

Author: lhsacchi

.github/workflows/doxygen.yml

@@ -23,4 +23,5 @@ jobs:
         uses: peaceiris/actions-gh-pages@v3
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_branch: gh-pages   # <<< força branch gh-pages
           publish_dir: ./docs/html