Bump sphinx from 7.3.7 to 8.0.2 in /client

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.3.7 to 8.0.2.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v7.3.7...v8.0.2)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

client/pyproject.toml

@@ -34,7 +34,7 @@ certgrinder = "certgrinder.certgrinder:main"
 [project.optional-dependencies]
 dev = ["twine == 5.1.0", "pre-commit == 3.7.1", "setuptools-scm == 8.1.0", "build==1.2.1"]
 test = ["pytest == 8.2.2", "pytest-cov==5.0.0", "tox == 4.15.1"]
-docs = ["Sphinx==7.3.7", "sphinx-rtd-theme==2.0.0", "sphinx-argparse==0.4.0"]
+docs = ["Sphinx==8.0.2", "sphinx-rtd-theme==2.0.0", "sphinx-argparse==0.4.0"]
 
 [project.urls]
 homepage = "https://github.com/tykling/certgrinder"