Update sphinx requirement from <7.1 to <7.4

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/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v3.5.0...v7.3.6)

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

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

setup.cfg

@@ -57,6 +57,6 @@ docs =
 	# local
 
 	# workaround for sphinx-doc/sphinx#11543
-	sphinx < 7.1
+	sphinx < 7.4
 
 [options.entry_points]