build(deps): bump sphinx in /docs in the minor-and-patch group (#574)

Bumps the minor-and-patch group in /docs with 1 update: [sphinx](https://github.com/sphinx-doc/sphinx).


Updates `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
  dependency-group: minor-and-patch
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -1,4 +1,4 @@
 furo==2024.8.6
-sphinx==8.0.2
+sphinx==8.1.3
 sphinx-click==6.0.0
 myst_parser==4.0.0