Build(deps): Bump sphinx from 8.0.2 to 8.1.3

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 8.0.2 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](sphinx-doc/sphinx@v8.0.2...v8.1.3)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-version: 8.1.3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

constraints.txt

@@ -48,7 +48,7 @@ setuptools==80.9.0
 setuptools-scm==9.2.2
 snowballstemmer==3.0.1
 sortedcontainers==2.4.0
-Sphinx==8.0.2
+Sphinx==8.1.3
 sphinx-rtd-theme==3.0.2
 sphinxcontrib-applehelp==2.0.0
 sphinxcontrib-devhelp==2.0.0