Fix link in readme (#351)

Author: sfod

README.rst

@@ -1,6 +1,6 @@
 New Version Available	
 =============================
-A new AWS IoT Device SDK is [now available](https://github.com/awslabs/aws-iot-device-sdk-python-v2). It is a complete rework, built to improve reliability, performance, and security. We invite your feedback!	
+A new AWS IoT Device SDK is `now available <https://github.com/awslabs/aws-iot-device-sdk-python-v2>`__. It is a complete rework, built to improve reliability, performance, and security. We invite your feedback!
 
 This SDK will no longer receive feature updates, but will receive security updates.