Update alert rule for kubelet

Update alert rule check kubelet down ratio from 1% to 10%.
In #774 , it is changed to 1%, so returns to 10%.

assets/prometheus/rules/kubelet.rules.yaml

@@ -28,7 +28,7 @@ groups:
       description: Prometheus failed to scrape {{ $value }}% of kubelets.
   - alert: K8SKubeletDown
     expr: (absent(up{job="kubelet"} == 1) or count(up{job="kubelet"} == 0) / count(up{job="kubelet"}))
-      * 100 > 1
+      * 100 > 10
     for: 1h
     labels:
       severity: critical

manifests/prometheus/prometheus-k8s-rules.yaml

@@ -365,7 +365,7 @@ data:
           description: Prometheus failed to scrape {{ $value }}% of kubelets.
       - alert: K8SKubeletDown
         expr: (absent(up{job="kubelet"} == 1) or count(up{job="kubelet"} == 0) / count(up{job="kubelet"}))
-          * 100 > 1
+          * 100 > 10
         for: 1h
         labels:
           severity: critical