Remove python 2 support in README

Author: davesque

README.rst

@@ -21,7 +21,7 @@ variable defaults should be safe.
 Requirements
 ------------
 
-* Python (2.7, 3.5, 3.6, 3.7)
+* Python (3.5, 3.6, 3.7)
 * Django (1.11, 2.0, 2.1)
 * Django REST Framework (3.5, 3.6, 3.7, 3.8, 3.9)