Bump addon-resizer for metrics-server to 1.8.11

The current version, 1.8.10, is vulnerable to kubernetes/autoscaler#3294

Author: mm4tt

cluster/addons/metrics-server/metrics-server-deployment.yaml

@@ -64,7 +64,7 @@ spec:
           name: https
           protocol: TCP
       - name: metrics-server-nanny
-        image: k8s.gcr.io/addon-resizer:1.8.10
+        image: k8s.gcr.io/addon-resizer:1.8.11
         resources:
           limits:
             cpu: 100m