Scheduled weekly dependency update for week 13 (#356)

* Update aiohttp from 3.1.0 to 3.1.1

* Update docker from 3.1.4 to 3.2.1

* Update python-dateutil from 2.7.1 to 2.7.2

* Update sqlalchemy from 1.2.5 to 1.2.6

Author: pyup.io bot

requirements-dev.txt

@@ -1,19 +1,19 @@
 aiohttp-jinja2==0.17.0
 aiohttp-security==0.2.0
 aiohttp-session==2.3.0
-aiohttp==3.1.0
+aiohttp==3.1.1
 aiomysql==0.0.12
 aiopg==0.13.2
 coverage==4.5.1
-docker==3.1.4
+docker==3.2.1
 flake8==3.5.0
 ipdb==0.11
 motor==1.2.1
 pytest-cov==2.5.1
 pytest-sugar==0.9.1
 pytest==3.5.0
-python-dateutil==2.7.1
-sqlalchemy==1.2.5
+python-dateutil==2.7.2
+sqlalchemy==1.2.6
 trafaret==2.0.0a1
 pymysql==0.8.0
 -r requirements-doc.txt