Bump sphinx from 7.4.7 to 8.1.3

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.4.7 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@v7.4.7...v8.1.3)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-version: 8.1.3
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

poetry.lock

@@ -33,7 +33,7 @@ certifi = ">=2022.5.18,<2027.0.0"
 black = "^26.3.1"
 mypy = "^1.19"
 types-urllib3 = "^1.26.25"
-Sphinx = "^7.4.7"
+Sphinx = "^8.1.3"
 sphinx-rtd-theme = "^3.1.0"
 # keep this in sync with docs/requirements.txt for readthedocs.org
 sphinx-autodoc-typehints = "^2.3.0"