Update pytest-cov requirement from <6.0.0,>=2.12.0 to >=2.12.0,<7.0.0

Updates the requirements on [pytest-cov](https://github.com/pytest-dev/pytest-cov) to permit the latest version.
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v2.12.0...v6.0.0)

---
updated-dependencies:
- dependency-name: pytest-cov
  dependency-type: direct:production
...

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

Author: dependabot[bot]

requirements-tests.txt

@@ -3,6 +3,6 @@ httpx >=0.22.0
 mypy == 1.11.2
 pytest >=7.1.3,<9.0.0
 pytest-asyncio==0.24.0
-pytest-cov >=2.12.0,<6.0.0
+pytest-cov >=2.12.0,<7.0.0
 pytest-django
 ruff ==0.6.8