[README] updating travis-ci badges

Author: truthbk

README.md

@@ -1,7 +1,7 @@
 Puppet & Datadog
 ================
 
-[![Build Status](https://travis-ci.org/DataDog/puppet-datadog-agent.svg?branch=master)](https://travis-ci.org/DataDog/puppet-datadog-agent)
+[![Build Status](https://travis-ci.com/DataDog/puppet-datadog-agent.svg?branch=master)](https://travis-ci.com/DataDog/puppet-datadog-agent)
 
 Description
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