Update pytest-cov requirement from <4.2,>=2.10 to >=2.10,<5.1

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@v2.10.0...v5.0.0)

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

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

setup.py

@@ -43,7 +43,7 @@ def read(*parts):
 tests_require = [
     'codecov==2.1.*',
     'coverage>=5.3,<7.5',
-    'pytest-cov>=2.10,<4.2',
+    'pytest-cov>=2.10,<5.1',
     'pytest-env==0.6,<1.2',
     'pytest-mock>=3.11,<3.15',
     'pytest>=6.1,<8.2',