Bump coverage from 7.0.3 to 7.4.1

Bumps [coverage](https://github.com/nedbat/coveragepy) from 7.0.3 to 7.4.1.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@7.0.3...7.4.1)

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

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

docs/requirements.txt

@@ -2,7 +2,7 @@ sphinx_rtd_theme
 paho-mqtt>=1.5.0
 requests>=2.19.1
 retrying>=1.3.3
-coverage==7.0.3
+coverage==7.4.1
 aiohttp[speedups]>=3.6.1
 pytest-aiohttp
 proxy.py