Bump sphinx from 4.0.2 to 4.1.2 (#467)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 4.0.2 to 4.1.2.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/4.x/CHANGES)
- [Commits](sphinx-doc/sphinx@v4.0.2...v4.1.2)

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

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

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

Author: dependabot[bot]

requirements-dev.txt

@@ -17,5 +17,5 @@ pytest-aiohttp==0.3.0
 pytest-cov==2.12.1
 pytest-cov==2.12.1
 pytest-sugar==0.9.4
-sphinx==4.0.2
+sphinx==4.1.2
 yarl==1.6.3