Update pytest-cov>=2.5.1,<=2.9
Due to the conflict with pytest
pytest-cov 2.10.0 has requirement pytest>=4.6, but you'll have pytest 3.10.1 which is incompatible.
@@ -16,7 +16,7 @@ pytest>=3.6.0,<4.0
# Pytest plugin for measuring coverage.
# License: MIT
# Upstream url: https://github.com/pytest-dev/pytest-cov
-pytest-cov>=2.5.1,<3.0
+pytest-cov>=2.5.1,<=2.9
# Rolling backport of unittest.mock for all Pythons
# License: BSD
