Bump pytest from 6.2.1 to 6.2.2

Bumps [pytest](https://github.com/pytest-dev/pytest) from 6.2.1 to 6.2.2.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/master/CHANGELOG.rst)
- [Commits](https://github.com/pytest-dev/pytest/compare/6.2.1...6.2.2)

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

requirements-dev.txt

@@ -1,11 +1,11 @@
 -e .
 flake8==3.8.4
 async-timeout==3.0.1
-pytest==6.1.2
+pytest==6.2.2
 pytest-cov==2.10.1
-pytest-mock==3.3.1
+pytest-mock==3.4.0
-coverage==5.3
+coverage==5.3.1
-sphinx==3.3.1
+sphinx==3.4.1
 pep257==0.7.0
 aiohttp-session==2.9.0
 aiopg[sa]==1.1.0