add server-side validation support to kubectl

hack/testdata/invalid-deployment-unknown-and-duplicate-fields.yaml

@@ -0,0 +1,24 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: invalid-nginx-deployment
+  labels:
+    app: nginx
+spec:
+  replicas: 3
+  replicas: 4
+  foo: bar
+  baz: baq
+  selector:
+    matchLabels:
+      app: nginx
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.14.2
+        ports:
+        - containerPort: 80