Bump coverage from 6.2 to 6.4.3 (#108)

Bumps [coverage](https://github.com/nedbat/coveragepy) from 6.2 to 6.4.3.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@6.2...6.4.3)

---
updated-dependencies:
- dependency-name: coverage
  dependency-type: direct:development
  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-dev.txt

@@ -1,7 +1,7 @@
 attribution==1.5.2
 black==22.6.0
 codecov==2.1.12
-coverage==6.2
+coverage==6.4.3
 flit==3.7.1
 flake8==5.0.4
 mypy==0.971