kube-prometheus: fix alert rule K8SManyNodesNotReady (#1313)

* kube-prometheus: fix alert rule K8SManyNodesNotReady

* fix alert "K8SManyNodesNotReady" in helm templates & make generate

* Use sync_kube_prometheus.py to make rules in helm in sync

assets/prometheus/rules/kubelet.rules.yaml

@@ -13,7 +13,7 @@ groups:
   - alert: K8SManyNodesNotReady
     expr: count(kube_node_status_condition{condition="Ready",status="true"} == 0)
       > 1 and (count(kube_node_status_condition{condition="Ready",status="true"} ==
-      0) / count(kube_node_status_condition{condition="Ready",status="true"})) > 0.2
+      0) / count(kube_node_status_condition{condition="Ready",status="true"})) * 100 > 20
     for: 1m
     labels:
       severity: critical