Bump coverage from 7.8.0 to 7.9.0 in /requirements

Bumps [coverage](https://github.com/nedbat/coveragepy) from 7.8.0 to 7.9.0.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@7.8.0...7.9.0)

---
updated-dependencies:
- dependency-name: coverage
  dependency-version: 7.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements/coverage.txt

@@ -1,2 +1,2 @@
-coverage==7.8.0
+coverage==7.9.0
 toml==0.10.2