Update pytest from 4.4.1 to 4.4.2 (#623)

Author: pyup-bot

requirements-development.txt

@@ -8,7 +8,7 @@ flake8==3.7.7
 flake8-isort==2.7.0
 isort==4.3.18
 mock==3.0.4
-pytest==4.4.1
+pytest==4.4.2
 pytest-cov==2.7.1
 pytest-django==3.4.8
 pytest-factoryboy==2.0.2