Bump pytest-cov from 3.0.0 to 4.0.0

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 3.0.0 to 4.0.0.
- [Release notes](https://github.com/pytest-dev/pytest-cov/releases)
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v3.0.0...v4.0.0)

---
updated-dependencies:
- dependency-name: pytest-cov
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

test-requirements.txt

@@ -1,6 +1,6 @@
 Faker==15.0.0
 pytest==7.1.1
-pytest-cov==3.0.0
+pytest-cov==4.0.0
 gevent==21.12.0; "PyPy" not in platform_python_implementation
 pylibmc==1.6.1; sys.platform != 'win32'
 python-memcached==1.59