fix build link

Author: Peter Olamit

README.rst

@@ -1,5 +1,5 @@
 .. image:: https://travis-ci.org/hyperwallet/python-sdk.svg?branch=master
-:target: https://travis-ci.org/hyperwallet/python-sdk.svg?branch=master
+:target: https://travis-ci.org/hyperwallet/python-sdk/builds
 .. image:: https://coveralls.io/repos/github/hyperwallet/python-sdk/badge.svg?branch=master
 :target: https://coveralls.io/github/hyperwallet/python-sdk?branch=master