Set namespace as default

This gets around a bug in Spinnaker where the namespace, if missing in the manifest, is set to "spinnaker".

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=192825895

java/google/registry/proxy/kubernetes/proxy-deployment-alpha.yaml

@@ -1,6 +1,7 @@
 apiVersion: apps/v1
 kind: Deployment
 metadata:
+  namespace: default
   name: proxy-deployment
   labels:
     app: proxy
@@ -51,6 +52,7 @@ spec:
 apiVersion: autoscaling/v2beta1
 kind: HorizontalPodAutoscaler
 metadata:
+  namespace: default
   name: proxy-autoscale
   labels:
     app: proxy

java/google/registry/proxy/kubernetes/proxy-service.yaml

@@ -1,6 +1,7 @@
 kind: Service
 apiVersion: v1
 metadata:
+  namespace: default
   name: proxy-service
 spec:
   selector: