Update pytest-cov requirement from ~=2.12 to ~=3.0

Updates the requirements on [pytest-cov](https://github.com/pytest-dev/pytest-cov) to permit the latest version.
- [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@v2.12.0...v3.0.0)

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

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

requirements-test.txt

@@ -6,5 +6,5 @@ mypy==0.960
 pylint~=2.14
 pylint-strict-informational==0.1
 pytest~=7.1
-pytest-cov~=2.12
+pytest-cov~=3.0
 pytest-homeassistant-custom-component>=0.8