build(deps-dev): update pytest-cov requirement from ^2.12.1 to ^3.0.0 (…

…#153)

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@v2.12.1...v3.0.0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pyproject.toml

@@ -35,7 +35,7 @@ flake8-pyi = "^20.10.0"
 isort = "^5.9.2"
 mypy = "^0.910"
 pytest = "^6.2.4"
-pytest-cov = "^2.12.1"
+pytest-cov = "^3.0.0"
 pytest-mock = "^3.6.1"
 tox = "^3.23.1"