Bump sphinx from 7.4.7 to 8.0.2 (#482)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.4.7 to 8.0.2.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v7.4.7...v8.0.2)

---
updated-dependencies:
- dependency-name: sphinx
  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>
Co-authored-by: Sebastian Blauth <sebastian.blauth@itwm.fraunhofer.de>

docs/requirements.txt

@@ -1,7 +1,7 @@
 numpy>=1.22.2
 matplotlib
 scipy
-Sphinx==7.4.7
+Sphinx==8.0.2
 sphinx-argparse==0.5.2
 sphinx-copybutton==0.5.2
 meshio==5.3.5