Upstream Changes:

   - coredns v1.2.5 (https://github.com/coredns/coredns/releases/tag/v1.2.5)

NOTE:

   - Switch image repo to https://hub.docker.com/r/coredns/coredns/ (https://github.com/kubernetes-incubator/kubespray/pull/3595#issuecomment-433962973)