Scheduled monthly dependency update for November (#49)

* Update aiohttp from 3.3.2 to 3.4.4

* Update black from 18.6b3 to 18.9b0

* Update gidgethub from 2.5.0.post1 to 3.0.0

* Update requests from 2.19.1 to 2.20.0

Author: pyup-bot

requirements.txt

@@ -1,7 +1,7 @@
-aiohttp==3.3.2
-black==18.6b3
+aiohttp==3.4.4
+black==18.9b0
 cachetools==2.1.0
 celery==4.2.1
-gidgethub==2.5.0.post1
-requests==2.19.1
+gidgethub==3.0.0
+requests==2.20.0
 redis==2.10.6