Bump codecov from 2.1.11 to 2.1.12 in /src/requirements

Bumps [codecov](https://github.com/codecov/codecov-python) from 2.1.11 to 2.1.12.
- [Release notes](https://github.com/codecov/codecov-python/releases)
- [Changelog](https://github.com/codecov/codecov-python/blob/master/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-python/compare/v2.1.11...v2.1.12)

---
updated-dependencies:
- dependency-name: codecov
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

src/requirements/dev.txt

@@ -3,7 +3,7 @@
 django-debug-toolbar==3.2.1
 factory_boy==3.2.0
 coverage==5.5
-codecov==2.1.11
+codecov==2.1.12
 black==21.7b0
 pre-commit==2.13.0
 isort==5.9.3