build(deps-dev): bump sphinx from 2.2.1 to 2.2.2

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 2.2.1 to 2.2.2.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES)
- [Commits](sphinx-doc/sphinx@v2.2.1...v2.2.2)

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

requirements/dev.txt

@@ -1,4 +1,4 @@
-Sphinx==2.2.1
+Sphinx==2.2.2
 check-manifest==0.40
 cogapp
 flake8==3.7.9