Update pytest from 3.0.6 to 3.4.1

requirements.txt

@@ -2,7 +2,7 @@ botstory==0.1.5
 
 emoji==0.4.5
 gunicorn==19.6.0
-pytest==3.0.6
+pytest==3.4.1
 pytest-aiohttp==0.1.3
 pytest-asyncio==0.5.0
 pytest-catchlog==1.2.2