Bump pytest-cov from 6.0.0 to 6.1.1 in /requirements

Bumps [pytest-cov](https://github.com/pytest-dev/pytest-cov) from 6.0.0 to 6.1.1.
- [Changelog](https://github.com/pytest-dev/pytest-cov/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest-cov@v6.0.0...v6.1.1)

---
updated-dependencies:
- dependency-name: pytest-cov
  dependency-version: 6.1.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements/requirements_test.txt

@@ -5,7 +5,7 @@ imageio==2.37.0
 imageio-ffmpeg==0.6.0
 pypandoc_binary==1.15
 pytest==8.3.5
-pytest-cov==6.0.0
+pytest-cov==6.1.1
 pytest-order==1.3.0
 pytest-rerunfailures==15.0
 pyvista==0.45.0