update bashboard to v2.0.0-beta3

Author: dfateyev

addons/kubernetes-dashboard-beta.yaml

@@ -192,7 +192,7 @@ spec:
     spec:
       containers:
         - name: kubernetes-dashboard
-          image: kubernetesui/dashboard:v2.0.0-beta2
+          image: kubernetesui/dashboard:v2.0.0-beta3
           imagePullPolicy: Always
           ports:
             - containerPort: 8443