Bump codecov from 2.0.16 to 2.0.22 in /src/requirements

Bumps [codecov](https://github.com/codecov/codecov-python) from 2.0.16 to 2.0.22.
- [Release notes](https://github.com/codecov/codecov-python/releases)
- [Changelog](https://github.com/codecov/codecov-python/blob/v2.0.22/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-python/compare/v2.0.16...v2.0.22)

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

src/requirements/dev.txt

@@ -3,7 +3,7 @@
 django-debug-toolbar==2.2
 factory_boy==2.12.0
 coverage==4.5.4
-codecov==2.0.16
+codecov==2.0.22
 black==19.10b0
 pre-commit==2.1.1
 isort==4.3.21