Bump sphinx from 4.0.0 to 4.0.1 (#59)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 4.0.0 to 4.0.1.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/4.x/CHANGES)
- [Commits](sphinx-doc/sphinx@v4.0.0...v4.0.1)

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

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

requirements-dev.txt

@@ -1,6 +1,6 @@
 isort==5.8.0
 black==21.5b0
-sphinx==4.0.0
+sphinx==4.0.1
 pytest==6.2.4
 pytest-cov==2.11.1
 pytest-xdist==2.2.1