Update pytest-cov requirement from ~=6.0.0 to ~=6.1.1

Updates the requirements on [pytest-cov](https://github.com/pytest-dev/pytest-cov) to permit the latest version.
- [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
...

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

Author: dependabot[bot]

requirements_test.txt

@@ -54,7 +54,7 @@ jax[cpu]==0.4.30
 # tests and style checking
 pytest~=8.3.2
 pytest-mock~=3.14.0
-pytest-cov~=6.0.0
+pytest-cov~=6.1.1
 pylint==3.2.6
 mypy==1.11.1
 pycodestyle==2.12.1