⬆️ Update sphinx requirement

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/v8.0.2/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v4.5.0...v8.0.2)

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

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

setup.py

@@ -38,7 +38,7 @@ def _parse_requirements(path, encoding="utf-8"):
     install_requires=base_requirements,
     extras_require={
         "doc": [
-            "sphinx>=4.5.0,<8.0.0",
+            "sphinx>=4.5.0,<9.0.0",
             "sphinx_rtd_theme>=1.0,<1.5",
             "sphinx-markdown-tables~=0.0.15",
             "sphinx-click>=3.1,<5.2",