Update aiohttp from 3.4.4 to 3.5.0 (#415)

Author: pyup-bot

requirements_dev.txt

@@ -6,7 +6,7 @@ wheel==0.32.2  # pyup: update minor
 cryptography==2.4.1  # pyup: update minor
 psycopg2-binary==2.7.6.1  # pyup: update minor
 sanic==0.8.3  # pyup: update minor
-aiohttp==3.4.4  # pyup: update minor
+aiohttp==3.5.0  # pyup: update minor
 tornado==5.1.1  # pyup: update minor
 async_generator==1.10  # pyup: update minor
 quart==0.7.0;python_version>="3.7"  # pyup: update minor