Bump coverage from 7.3.4 to 7.4.0 (#304)

Bumps [coverage](https://github.com/nedbat/coveragepy) from 7.3.4 to 7.4.0.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@7.3.4...7.4.0)

---
updated-dependencies:
- dependency-name: coverage
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements-test.txt

@@ -1,5 +1,5 @@
 aioresponses==0.7.6
-coverage==7.3.4
+coverage==7.4.0
 mypy==1.8.0
 pytest-asyncio==0.23.2
 pytest-cov==4.1.0