Bump sphinx from 7.3.7 to 8.1.3 (#1269)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.3.7 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](sphinx-doc/sphinx@v7.3.7...v8.1.3)

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

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

Author: dependabot[bot]

requirements-dev.txt

@@ -24,6 +24,6 @@ psycopg2==2.9.10
 
 # docs
 pygments==2.18.0
-sphinx==7.3.7
+sphinx==8.1.3
 sphinxcontrib-asyncio==0.3.0
 sphinxcontrib-spelling==8.0.0; platform_system!="Windows"  # We only use it in CI