Update pytest-django from 3.5.0 to 3.5.1 (#672)

Author: pyup-bot

requirements-development.txt

@@ -9,7 +9,7 @@ flake8-isort==2.7.0
 isort==4.3.21
 pytest==4.6.3
 pytest-cov==2.7.1
-pytest-django==3.5.0
+pytest-django==3.5.1
 pytest-factoryboy==2.0.3
 recommonmark==0.5.0
 Sphinx==2.1.2