Scheduled weekly dependency update for week 43 (#212)

* Update flake8 from 3.4.1 to 3.5.0

* Update sphinx from 1.6.4 to 1.6.5

* Update aiohttp from 2.2.5 to 2.3.1

Author: pyup.io bot

requirements-dev.txt

@@ -1,14 +1,14 @@
-flake8==3.4.1
+flake8==3.5.0
 coverage==4.4.1
-sphinx==1.6.4
+sphinx==1.6.5
 pep257==0.7.0
 -e .
 aioredis==0.3.3
 cryptography==2.1.1
 pynacl==1.1.2
 pytest-aiohttp==0.1.3
 pytest-cov==2.5.1
-aiohttp==2.2.5
+aiohttp==2.3.1
 multidict==3.3.0
 chardet==3.0.4
 yarl==0.13.0