Bump coverage from 7.6.7 to 7.6.8 in /requirements (#1923)

Bumps [coverage](https://github.com/nedbat/coveragepy) from 7.6.7 to 7.6.8.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](coveragepy/coveragepy@7.6.7...7.6.8)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Paul Profizi <[email protected]>

Author: dependabot[bot]

requirements/requirements_test.txt

@@ -1,5 +1,5 @@
 ansys-platform-instancemanagement==1.1.2
-coverage==7.6.7
+coverage==7.6.8
 imageio==2.36.0
 imageio-ffmpeg==0.5.1
 pytest==8.3.3