Reinstate Bintray Plugin Repository
Reinstate Bintray Plugin Repository

A previous commit removed <repositories> and <pluginRepositories> to comply with Maven's
guidelines. Unfortunately one of our required plugins does not have a recent version
available outside of Bintray. This commit reinstates the necessary repository reference.

Signed-off-by: Paul Harris <859d2524afe9d1b926cf5c02089ad1cbab640cc0@pivotal.io>

cloudfoundry/cf-java-client,cloudfoundry/cf-java-client,cloudfoundry/cf-java-client