Bump sphinx from 7.4.7 to 8.1.3

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.4.7 to 8.1.3.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/v8.1.3/CHANGES.rst)
- [Commits](https://github.com/sphinx-doc/sphinx/compare/v7.4.7...v8.1.3

)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>