Bump sphinx from 5.1.0 to 5.1.1 in /extra_requirements (#245)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 5.1.0 to 5.1.1.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/5.x/CHANGES)
- [Commits](sphinx-doc/sphinx@v5.1.0...v5.1.1)

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

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

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

extra_requirements/requirements-docs.txt

@@ -2,7 +2,7 @@
 nbsphinx==0.8.9
 recommonmark==0.7.1
 sphinx_rtd_theme==1.0.0
-sphinx==5.1.0
+sphinx==5.1.1
 sphinxcontrib_applehelp==1.0.2
 sphinxcontrib_devhelp==1.0.2
 sphinxcontrib_htmlhelp==2.0.0