build(deps): update sphinx requirement from <8.2 to <8.3

Updates the requirements on [sphinx](https://github.com/sphinx-doc/sphinx) to permit the latest version.
- [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@v0.1.61611...v8.2.1)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
...

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

requirements-docs.txt

@@ -1,5 +1,5 @@
 gevent
 shibuya
-sphinx<8.2
+sphinx<8.3
 sphinx-autodoc-typehints[type_comments]>=1.8.0
 typing-extensions