Bump sphinx from 7.2.2 to 8.2.1

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.2.2 to 8.2.1.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/v8.2.1/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v7.2.2...v8.2.1)

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

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

Author: dependabot[bot]

docs/requirements.txt

@@ -1 +1 @@
-sphinx == 7.2.2
+sphinx == 8.2.1