Bump sphinx from 5.3.0 to 6.1.3

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 5.3.0 to 6.1.3.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES)
- [Commits](sphinx-doc/sphinx@v5.3.0...v6.1.3)

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

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

Author: dependabot[bot]

docs/requirements.txt

@@ -1,5 +1,5 @@
 importlib-metadata==6.0.0
 myst-parser==0.18.1
 readthedocs-sphinx-search==0.1.2
-Sphinx==5.3.0
+Sphinx==6.1.3
 sphinx-rtd-theme==1.1.1