Update redis from 3.0.1 to 3.2.1

Author: pyup-bot

requirements/base.txt

@@ -9,6 +9,6 @@ Markdown==3.1
 psycopg2==2.7.5 --no-binary psycopg2
 Pygments==2.3.1
 raven==6.10.0
-redis==3.0.1
+redis==3.2.1
 requests==2.21.0
 whitenoise==4.1.2