Bump actions/deploy-pages from 2 to 4

Bumps [actions/deploy-pages](https://github.com/actions/deploy-pages) from 2 to 4.
- [Release notes](https://github.com/actions/deploy-pages/releases)
- [Commits](actions/deploy-pages@v2...v4)

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

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

.github/workflows/ci.yml

@@ -159,7 +159,7 @@ jobs:
           path: doc/
 
       - name: Deploy to GitHub pages
-        uses: actions/deploy-pages@v2
+        uses: actions/deploy-pages@v4
         if: github.event_name == 'push'
             && github.ref == 'refs/heads/main'
             && matrix.deploy-doc == 'deploy-doc'