Bump sphinx from 8.1.0 to 8.1.3

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 8.1.0 to 8.1.3.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v8.1.0...v8.1.3)

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

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

requirements-dev.txt

@@ -7,4 +7,4 @@ flake8-import-order==0.18.2
 flake8-requirements==2.2.1
 mypy==1.11.2; implementation_name=="cpython"
 pre-commit==4.0.1
-sphinx==8.1.0
+sphinx==8.1.3