build(deps): bump coverage from 6.3.2 to 6.4

Bumps [coverage](https://github.com/nedbat/coveragepy) from 6.3.2 to 6.4.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@6.3.2...6.4)

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

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

requirements-test.txt

@@ -4,7 +4,7 @@
 -r requirements-pinned.txt
 
 # additional test tools for linting and coverage measurement
-coverage==6.3.2
+coverage==6.4
 black==22.3.0
 isort==5.10.1
 pylint==2.13.8