Update sphinx requirement from <7.2.5 to <7.3.8

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...v7.3.7)

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

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

pyproject.toml

@@ -39,7 +39,7 @@ docs = [
 	# upstream
 	"sphinx >= 3.5",
 	# workaround for sphinx/sphinx-doc#11662
-	"sphinx < 7.2.5",
+	"sphinx < 7.3.8",
 	"jaraco.packaging >= 9.3",
 	"rst.linker >= 1.9",
 	"furo",