Bump pytest-cov from 2.11.1 to 2.12.1 (#29)

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 2.11.1 to 2.12.1.
- [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@v2.11.1...v2.12.1)

---
updated-dependencies:
- dependency-name: pytest-cov
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

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

Author: dependabot[bot]

poetry.lock

@@ -31,7 +31,7 @@ black = "^21.4b2"
 # tests
 pytest = "^6.2.4"
 pytest-asyncio = "^0.14.0"
-pytest-cov = "^2.11.1"
+pytest-cov = "^2.12.1"
 
 [tool.poetry.plugins."gino.extensions"]
 "quart" = "gino_quart"