Merge pull request #232 from aio-libs/pyup-update-pytest-3.2.4-to-3.3.1

Update pytest to 3.3.1

Author: asvetlov

requirements-dev.txt

@@ -2,7 +2,7 @@ coverage==4.4.1
 flake8==3.4.1
 ipdb==0.10.2
 ipython==6.1.0
-pytest==3.2.4
+pytest==3.3.1
 pytest-cov==2.5.1
 pytest-sugar==0.9.0
 sphinx==1.6.4