add six package to bootstrap role
add six package to bootstrap role

kubernetes-sigs/kubespray,Atoms/kubespray,ayaz/kubespray,sgm-media/kargo,Atoms/kubespray,Abdelsalam-Abbas/kubespray_fork,Atoms/kubespray,Lendico/kargo,kubespray/kargo,Lendico/kargo,kubespray/kargo,Abdelsalam-Abbas/kubespray_fork,ayaz/kubespray,kubernetes-incubator/kubespray,kubernetes-incubator/kargo,insequent/kargo,insequent/kargo,kubernetes-sigs/kubespray,kubernetes-sigs/kubespray,kubernetes-sigs/kubespray,kubernetes-incubator/kubespray,kubernetes-incubator/kargo,Atoms/kubespray,sgm-media/kargo