Merge pull request #193 from aio-libs/pyup-update-pytest-cov-2.4.0-to-2.5.1

Update pytest-cov to 2.5.1

Author: jettify

requirements-dev.txt

@@ -3,7 +3,7 @@ flake8==3.4.1
 ipdb==0.10.2
 ipython==6.1.0
 pytest==3.1.3
-pytest-cov==2.4.0
+pytest-cov==2.5.1
 pytest-sugar==0.8.0
 sphinx==1.6.3
 sphinxcontrib-asyncio==0.2.0