Add in your POM:
<repositories>
<repository>
<id>bintray</id>
<url>http://dl.bintray.com/guestful/maven</url>
</repository>
</repositories>
and
<dependency>
<groupId>com.guestful.module</groupId>
<artifactId>guestful.module.twilio-client</artifactId>
<version>?</version>
</dependency>
Checkout last version here