chore(deps-dev): bump pytest-cov from 2.12.1 to 3.0.0

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 2.12.1 to 3.0.0.
- [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
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

Diff for: poetry.lock

@@ -41,7 +41,7 @@ flake8-fixme = "^1.1.1"
 flake8-isort = "^4.0.0"
 flake8-variables-names = "^0.0.4"
 isort = "^5.9.3"
-pytest-cov = "^2.12.1"
+pytest-cov = "^3.0.0"
 pytest-mock = "^3.5.1"
 pdoc3 = "^0.10.0"
 pytest-asyncio = "^0.15.1"