Scheduled weekly dependency update for week 14 (#264)

* Update cryptography from 2.2.1 to 2.2.2

* Update docker from 3.1.4 to 3.2.1

* Update pytest-mock from 1.7.1 to 1.8.0

* Update aiohttp from 3.1.0 to 3.1.2

Author: pyup.io bot

requirements-dev.txt

@@ -4,15 +4,15 @@ sphinx==1.7.2
 pep257==0.7.0
 -e .
 aioredis==1.1.0
-cryptography==2.2.1
-docker==3.1.4
+cryptography==2.2.2
+docker==3.2.1
 pynacl==1.2.1
 pytest==3.5.0
 pytest-aiohttp==0.3.0
 pytest-cov==2.5.1
-pytest-mock==1.7.1
+pytest-mock==1.8.0
 pytest-sugar==0.9.1
-aiohttp==3.1.0
+aiohttp==3.1.2
 multidict==4.1.0
 chardet==3.0.4
 yarl==1.1.1