Set metrics-server preferred address types

So, v0.3.0 changed how the options are specified, so it makes sense that
we needed to make this change. See:
* https://github.com/kubernetes/kubernetes/issues/44540#issuecomment-424508625
* https://github.com/kubernetes/kubernetes/issues/44540#issuecomment-425218584

From checking the address preferences configured on our API server i.e.
and then mirroring those options to metrics-server. See:
* https://github.com/kubernetes-incubator/metrics-server/issues/67#issuecomment-438421549

addons/metrics-server/v1.8.x.yaml

@@ -138,6 +138,9 @@ spec:
       - name: metrics-server
         image: gcr.io/google_containers/metrics-server-amd64:v0.3.1
         imagePullPolicy: Always
+        command:
+            - /metrics-server
+            - --kubelet-preferred-address-types=InternalIP,Hostname,ExternalIP
         volumeMounts:
         - name: tmp-dir
           mountPath: /tmp