chore(deps-dev): bump pytest-cov from 2.9.0 to 2.10.0

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 2.9.0 to 2.10.0.
- [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@v2.9.0...v2.10.0)

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

dev-requirements.txt

@@ -3,7 +3,7 @@ coveralls==1.7.0;python_version<'3.0'
 coveralls==2.0.0;python_version>='3.6'
 pytest==4.6.9;python_version<'3.0'
 pytest==5.4.3;python_version>='3.6'
-pytest-cov==2.9.0
+pytest-cov==2.10.0
 Sphinx==1.8.5;python_version<'3.0'
 Sphinx==3.1.0;python_version>='3.6'
 sphinx-bootstrap-theme==0.7.1