ci(deps): bump peaceiris/actions-gh-pages from 2 to 4

Bumps [peaceiris/actions-gh-pages](https://github.com/peaceiris/actions-gh-pages) from 2 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@v2...v4)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/docspublish.yml

@@ -31,7 +31,7 @@ jobs:
         token: ${{ secrets.PERSONAL_ACCESS_TOKEN_FOR_ORG }}
         file: 'docs/README.md'
     - name: Push doc to Github Page
-      uses: peaceiris/actions-gh-pages@v2
+      uses: peaceiris/actions-gh-pages@v4
       env:
         PERSONAL_TOKEN: ${{ secrets.PERSONAL_ACCESS_TOKEN }}
         PUBLISH_BRANCH: gh-pages