Update pytest-cov requirement from <5 to <6

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@v1.0...v5.0.0)

---
updated-dependencies:
- dependency-name: pytest-cov
  dependency-type: direct:production
...

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

pyproject.toml

@@ -124,7 +124,7 @@ scientific = [
 ]
 test = [
   "pytest<9",
-  "pytest-cov<5",
+  "pytest-cov<6",
   "pytest-timeout<3",
 ]
 [project.urls]