Bump sphinx from 6.1.3 to 6.2.1 (#856)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 6.1.3 to 6.2.1.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES)
- [Commits](sphinx-doc/sphinx@v6.1.3...v6.2.1)

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

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

requirements/doc.txt

@@ -1 +1 @@
-sphinx==6.1.3
+sphinx==6.2.1