build(deps): bump sphinx from 8.0.2 to 8.1.3 in /docs

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-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -300,9 +300,9 @@ snowballstemmer==2.2.0 \
     --hash=sha256:09b16deb8547d3412ad7b590689584cd0fe25ec8db3be37788be3810cbf19cb1 \
     --hash=sha256:c8e1716e83cc398ae16824e5572ae04e0d9fc2c6b985fb0f900f5f0c96ecba1a
     # via sphinx
-sphinx==8.0.2 \
-    --hash=sha256:0cce1ddcc4fd3532cf1dd283bc7d886758362c5c1de6598696579ce96d8ffa5b \
-    --hash=sha256:56173572ae6c1b9a38911786e206a110c9749116745873feae4f9ce88e59391d
+sphinx==8.1.3 \
+    --hash=sha256:09719015511837b76bf6e03e42eb7595ac8c2e41eeb9c29c5b755c6b677992a2 \
+    --hash=sha256:43c1911eecb0d3e161ad78611bc905d1ad0e523e4ddc202a58a821773dc4c927
     # via
     #   rules-python-docs (docs/pyproject.toml)
     #   myst-parser