build(deps): bump pytest-cov in /testing/plugins_integration

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 2.10.1 to 2.11.1.
- [Release notes](https://github.com/pytest-dev/pytest-cov/releases)
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](https://github.com/pytest-dev/pytest-cov/compare/v2.10.1...v2.11.1)

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

testing/plugins_integration/requirements.txt

@@ -2,7 +2,7 @@ anyio[curio,trio]==2.0.2
 django==3.1.5
 pytest-asyncio==0.14.0
 pytest-bdd==4.0.2
-pytest-cov==2.10.1
+pytest-cov==2.11.1
 pytest-django==4.1.0
 pytest-flakes==4.0.3
 pytest-html==3.1.1