Rkt 1.3.0 released

Version1.3.0 of the rkt container system has been released. "rktversion 1.3.0 improves handling of errors within app containers, tightenssecurity for rkt's modular stage1 images, and provides a more compatiblehandling of volumes when executing Docker container images rather thanrkt's native ACI image format. This release further develops the essentialsupport for rkt as a component of the Kubernetes clusterorchestrator."