Added minimum platform version requirements to the README.

Jarrad Lee · Jarrad Lee · commit a0affdf62ad5 · 2018-01-12T13:19:48.000-08:00
diff --git a/README.rst b/README.rst
@@ -39,6 +39,8 @@ To install the TeleSign Python SDK:
 
     $ pip install telesign
 
+Python **2.7+** is required for the TeleSign Python SDK.
+
 Authentication
 --------------
 
