Bump coverage from 7.8.2 to 7.9.1 in /requirements

Bumps [coverage](https://github.com/nedbat/coveragepy) from 7.8.2 to 7.9.1.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@7.8.2...7.9.1)

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

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

Author: dependabot[bot]

requirements/requirements_test.txt

@@ -1,5 +1,5 @@
 ansys-platform-instancemanagement==1.1.2
-coverage==7.8.2
+coverage==7.9.1
 graphviz==0.20.1
 imageio==2.37.0
 imageio-ffmpeg==0.6.0