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]

poetry.lock

@@ -25,7 +25,7 @@ apispec_webframeworks = "^0.5.2"
 [tool.poetry.dev-dependencies]
 pytest = "^6.2"
 black = {version = "^20.8b1",allow-prereleases = true}
-pytest-cov = "^2.11.1"
+pytest-cov = "^3.0.0"
 jsonschema = "^3.2.0"
 pylint = "^2.10.2"
 sphinx = "^4.1.1"