[UPDATE] Update sphinx requirement from <6,>=5 to >=5.3.0,<6

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/v5.3.0/CHANGES)
- [Commits](https://github.com/sphinx-doc/sphinx/compare/v5.0.0...v5.3.0)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-version: 5.3.0
  dependency-type: direct:production
...

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

pyproject.toml

@@ -39,7 +39,7 @@ dependencies = [
     "jinja2<4.0.0,>=3.1.6",
     "django-countries>=8.2.0,<9.0.0",
     "dict2xml>=1.7.8,<2.0.0",
-    "Sphinx<6,>=5",
+    "Sphinx>=5.3.0,<6",
     "tomli>=2.4.1,<3.0.0",
     "django-honeypot>=1.3.0,<2",
     "pydantic-extra-types>=2.11.1,<3.0.0",