Merge pull request #211 from aio-libs/pyup-update-sphinx-1.6.3-to-1.6.4

Update sphinx to 1.6.4

Author: jettify

requirements-dev.txt

@@ -5,6 +5,6 @@ ipython==6.1.0
 pytest==3.2.3
 pytest-cov==2.5.1
 pytest-sugar==0.9.0
-sphinx==1.6.3
+sphinx==1.6.4
 sphinxcontrib-asyncio==0.2.0
 sqlalchemy==1.1.14