Bump crazy-max/ghaction-github-pages from 3 to 4 (JSBSim-Team#957)

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

---
updated-dependencies:
- dependency-name: crazy-max/ghaction-github-pages
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/cpp-python-build.yml

@@ -919,7 +919,7 @@ jobs:
           touch documentation/html/.nojekyll
           sphinx-build -b html documentation documentation/html/python
       - name: Publish docs to GitHub Pages
-        uses: crazy-max/ghaction-github-pages@v3
+        uses: crazy-max/ghaction-github-pages@v4
         with:
           target_branch: gh-pages
           build_dir: build/documentation/html