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-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/ci-cd.yml

@@ -378,7 +378,7 @@ jobs:
       run: if [ -n "$GHPAGES_DEPLOY_KEY" ]; then echo "DEPLOY=true" >> $GITHUB_OUTPUT; fi
     - name: Deploy Docs to GitHub Pages
       if: steps.deployable.outputs.DEPLOY
-      uses: peaceiris/actions-gh-pages@v3
+      uses: peaceiris/actions-gh-pages@v4
       with:
         github_token: ${{ secrets.GHPAGES_DEPLOY_KEY }}
         publish_dir: docs-build