Update coverage requirement from ~=7.8 to ~=7.9

Updates the requirements on [coverage](https://github.com/nedbat/coveragepy) to permit the latest version.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](coveragepy/coveragepy@7.8.0...7.9.1)

---
updated-dependencies:
- dependency-name: coverage
  dependency-version: 7.9.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements_minimal.txt

@@ -3,7 +3,7 @@ contributors-txt>=0.7.4
 tbump~=6.11
 
 # Tools used to run tests
-coverage~=7.8
+coverage~=7.9
 pytest
 pytest-cov~=6.1
 mypy