Update diego-pipeline Dockerfile to base itself on golang-ci [finishes #91983262]
Update diego-pipeline Dockerfile to base itself on golang-ci [finishes #91983262]

Signed-off-by: Matt Royal <6463362714fdee6ae948b4a582165edffac2664e@pivotal.io>

cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release