Bump peaceiris/actions-gh-pages from 3 to 4

Bumps [peaceiris/actions-gh-pages](https://github.com/peaceiris/actions-gh-pages) from 3 to 4.
- [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@v3...v4)

---
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>

Author: dependabot[bot]

.github/workflows/docs.yml

@@ -27,7 +27,7 @@ jobs:
                   echo '<meta http-equiv="refresh" content="0; url=erudite">' > target/x86_64-unknown-linux-gnu/doc/index.html
             - name: Deploy to GitHub Pages
               if: ${{ github.event_name != 'pull_request' }}
-              uses: peaceiris/actions-gh-pages@v3
+              uses: peaceiris/actions-gh-pages@v4
               with:
                   github_token: ${{ secrets.DEPLOY_GITHUB_TOKEN }}
                   publish_dir: target/x86_64-unknown-linux-gnu/doc