Fix `coreos_dual` -> `coredns_dual` typo
Fix `coreos_dual` -> `coredns_dual` typo

See: e40368ae2bede83978523cb1d4c04866c322468e

kubernetes-sigs/kubespray,kubernetes-sigs/kubespray,kubernetes-incubator/kubespray,Atoms/kubespray,kubespray/kargo,insequent/kargo,Atoms/kubespray,kubernetes-sigs/kubespray,kubernetes-sigs/kubespray,Atoms/kubespray,kubernetes-incubator/kargo,kubespray/kargo,kubernetes-incubator/kargo,Atoms/kubespray,insequent/kargo,kubernetes-incubator/kubespray