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

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 5.0.0 to 6.0.0.
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v5.0.0...v6.0.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

testing/plugins_integration/requirements.txt

@@ -2,7 +2,7 @@ anyio[curio,trio]==4.6.2.post1
 django==5.1.2
 pytest-asyncio==0.24.0
 pytest-bdd==7.3.0
-pytest-cov==5.0.0
+pytest-cov==6.0.0
 pytest-django==4.9.0
 pytest-flakes==4.0.5
 pytest-html==4.1.1