Bump peaceiris/actions-gh-pages from 3.9.0 to 4.0.0 (#344)

Bumps [peaceiris/actions-gh-pages](https://github.com/peaceiris/actions-gh-pages) from 3.9.0 to 4.0.0.
- [Release notes](https://github.com/peaceiris/actions-gh-pages/releases)
- [Changelog](https://github.com/peaceiris/actions-gh-pages/blob/main/CHANGELOG.md)
- [Commits](peaceiris/actions-gh-pages@de7ea6f...4f9cc66)

---
updated-dependencies:
- dependency-name: peaceiris/actions-gh-pages
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build.yml

@@ -132,7 +132,7 @@ jobs:
           path: docs/_build/
       - name: upload docs to github pages
         if: github.event_name != 'pull_request' && github.ref == 'refs/heads/main' && runner.os == 'Linux'
-        uses: peaceiris/actions-gh-pages@de7ea6f8efb354206b205ef54722213d99067935 # pinned to v3.9.0
+        uses: peaceiris/actions-gh-pages@4f9cc6602d3f66b9c108549d475ec49e8ef4d45e # pinned to v4.0.0
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./docs/_build/html