update etcd download url in offline.yml
update etcd download url in offline.yml

Signed-off-by: bo.jiang <3d2eb430d7edbf0ec07b670ed378db7970ecadca@daocloud.io>

Atoms/kubespray,kubernetes-sigs/kubespray,kubernetes-sigs/kubespray,Atoms/kubespray,kubernetes-sigs/kubespray,kubernetes-sigs/kubespray,Atoms/kubespray,Atoms/kubespray