build(deps): bump sphinx from 8.0.2 to 8.1.3 (#1440)

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/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v8.0.2...v8.1.3)

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

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

Author: dependabot[bot]

docs/requirements-docs.txt

@@ -331,7 +331,7 @@ snowballstemmer==2.2.0
     # via sphinx
 soupsieve==2.6
     # via beautifulsoup4
-sphinx==8.0.2
+sphinx==8.1.3
     # via
     #   -r docs/requirements-docs.in
     #   nbsphinx