Bump sphinx from 8.0.2 to 8.1.3 (#296)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 8.0.2 to 8.1.3.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v8.0.2...v8.1.3)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pyproject.toml

@@ -31,7 +31,7 @@ Source = "https://github.com/sloria/doitlive/"
 
 [project.optional-dependencies]
 tests = ["pytest", "IPython>=8"]
-docs = ["sphinx==8.0.2", "sphinx-issues==4.1.0"]
+docs = ["sphinx==8.1.3", "sphinx-issues==4.1.0"]
 dev = ["doitlive[tests]", "tox", "pre-commit>=3.6,<5.0"]
 
 [project.scripts]