Bump actions/configure-pages from 3 to 4

Bumps [actions/configure-pages](https://github.com/actions/configure-pages) from 3 to 4.
- [Release notes](https://github.com/actions/configure-pages/releases)
- [Commits](actions/configure-pages@v3...v4)

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

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

Author: dependabot[bot]

.github/workflows/gh-pages.yml

@@ -28,7 +28,7 @@ jobs:
           bundler-cache: true
       - name: Setup Pages
         id: pages
-        uses: actions/configure-pages@v3
+        uses: actions/configure-pages@v4
       - name: Build with RDoc
         # Outputs to the './_site' directory by default
         run: bundle exec rake rdoc