Bump peaceiris/actions-gh-pages from 3 to 4 (#6197)

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](https://github.com/peaceiris/actions-gh-pages/compare/v3...v4)

---
updated-dependencies:
- dependency-name: peaceiris/actions-gh-pages
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/documentation-build.yml

@@ -28,7 +28,7 @@ jobs:
 
       - name: Deploy to cockatrice.github.io
         if: github.event_name != 'pull_request'
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           deploy_key: ${{ secrets.DOCS_DEPLOY_KEY }}
           external_repository: Cockatrice/cockatrice.github.io