Bump sphinx from 5.3.0 to 6.1.3 (#605)

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
...

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

docs/requirements.txt

@@ -14,4 +14,4 @@ typing-extensions>=4.2.0
 readthedocs-sphinx-ext==2.2.0
 seed_intersphinx_mapping
 sphinx-rtd-theme==1.1.1
-sphinx==5.3.0
+sphinx==6.1.3