Merge pull request #493 from fantix/pyup-update-cryptography-2.6.1-to-2.7

Update cryptography to 2.7

Author: fantix

requirements_dev.txt

@@ -3,7 +3,7 @@ pip==19.1  # pyup: update minor
 
 bumpversion==0.5.3  # pyup: update minor
 wheel==0.33.0  # pyup: update minor
-cryptography==2.6.1  # pyup: update minor
+cryptography==2.7  # pyup: update minor
 psycopg2-binary==2.8.1  # pyup: update minor
 sanic==19.3.1  # pyup: update minor
 aiohttp==3.5.0  # pyup: update minor