Update sphinx requirement from <3.4.0,>=3.0.3 to >=3.0.3,<7.3.0

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@v3.0.3...v7.2.6)

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

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

pyproject.toml

@@ -25,9 +25,9 @@ Homepage = "https://github.com/repo-helper/configconfig"
 Documentation = "https://configconfig.readthedocs.io/en/latest"
 
 [project.optional-dependencies]
-sphinx = [ "docutils", "sphinx<3.4.0,>=3.0.3", "sphinx-toolbox",]
+sphinx = [ "docutils", "sphinx>=3.0.3,<7.3.0", "sphinx-toolbox",]
 testing = [ "pytest",]
-all = [ "docutils", "pytest", "sphinx<3.4.0,>=3.0.3", "sphinx-toolbox",]
+all = [ "docutils", "pytest", "sphinx>=3.0.3,<7.3.0", "sphinx-toolbox",]
 
 [tool.mkrecipe]
 conda-channels = [ "conda-forge", "domdfcoding",]