verify_manifest_lists.go: fix "panic: could not parse "v1.18.6\n" as version [recovered]" issue
verify_manifest_lists.go: fix "panic: could not parse "v1.18.6\n" as version [recovered]" issue

verFromURL we get at first is v1.18.6\n, however version.MustParseGeneric can only parse
something like 1.18.6. so we should remove the first and last character

$ curl -s https://storage.googleapis.com/kubernetes-release/release/stable-1.txt
v1.18.6

Signed-off-by: Ma Xinjian <d1eaa362fbe20f4d1e94a590b52fa846afcd0e34@cn.fujitsu.com>

kubernetes/kubeadm,kubernetes/kubeadm