Update Java Buildpack

This change updates the Java buildpack submodule to version 2.0
Version 2.0 includes the following improvements:

* Output detection changes[1]
* Play Framework 2.2 support
* Spring Insight support[2]
* New Relic zero-touch support now works with user-provided services
  in addition to platform provided services[3]
* AppDynamics support[4]
* New abstractions and test support for building components
* Automatic download of MariaDB and PostgreSQL drivers

[1]: https://github.com/cloudfoundry/java-buildpack/commit/be124ef5a40fdc5e155a93f3f700410bd5687fc6
[2]: https://github.com/cloudfoundry/java-buildpack/blob/master/docs/framework-spring_insight.md
[3]: https://github.com/cloudfoundry/java-buildpack/blob/master/docs/framework-new_relic_agent.md#user-provided-service-optional
[4]: https://github.com/cloudfoundry/java-buildpack/blob/master/docs/framework-app_dynamics_agent.md