Bump actions/configure-pages from 5 to 6 (#14470)

Bumps [actions/configure-pages](https://github.com/actions/configure-pages) from 5 to 6.
- [Release notes](https://github.com/actions/configure-pages/releases)
- [Commits](actions/configure-pages@v5...v6)

---
updated-dependencies:
- dependency-name: actions/configure-pages
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/sphinx.yml

@@ -39,7 +39,7 @@ jobs:
           python-version: 3.14
           allow-prereleases: true
       - run: uv sync --group=docs
-      - uses: actions/configure-pages@v5
+      - uses: actions/configure-pages@v6
       - run: uv run sphinx-build -c docs . docs/_build/html
       - uses: actions/upload-pages-artifact@v4
         with: