Update sphinx requirement from ^4.3.1 to ^6.2.1 (#88)

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)
- [Commits](https://github.com/sphinx-doc/sphinx/compare/v4.3.1...v6.2.1)

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

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

pyproject.toml

@@ -31,7 +31,7 @@ pytest = "^7.0.1"
 pytest-asyncio = "^0.21.0"
 pytest-cov = "^4.0.0"
 ruff = "^0.0.264"
-Sphinx = "^4.3.1"
+Sphinx = "^6.2.1"
 sphinx-autoapi = "^2.0.1"
 sphinx-autodoc-typehints = "^1.12.0"
 sphinxcontrib-spelling = "^8.0.0"