Merge pull request #43896 from CaoShuFeng/list-meta

Automatic merge from submit-queue

Reorganize the output of "kubectl get -o json"

"resourceVersion" and "selfLink" are members of "metadata" rather than
the list. This change reorganize the struct to provide consistency with
other places.

Before this change:
```json
    "kind": "List",
    "metadata": {},
    "resourceVersion": "",
    "selfLink": ""
```
After this change:
```json
    "kind": "List",
    "metadata": {
        "resourceVersion": "",
        "selfLink": ""
    }
```

Reference:
https://github.com/kubernetes/kubernetes/blob/master/staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/types.go#L57



**Release note**:

```release-note
NONE
```

pkg/kubectl/cmd/get.go

@@ -362,8 +362,10 @@ func RunGet(f cmdutil.Factory, out, errOut io.Writer, cmd *cobra.Command, args [
 				},
 			}
 			if listMeta, err := meta.ListAccessor(obj); err == nil {
-				list.Object["selfLink"] = listMeta.GetSelfLink()
-				list.Object["resourceVersion"] = listMeta.GetResourceVersion()
+				list.Object["metadata"] = map[string]interface{}{
+					"selfLink":        listMeta.GetSelfLink(),
+					"resourceVersion": listMeta.GetResourceVersion(),
+				}
 			}
 
 			for _, item := range items {

pkg/kubectl/cmd/get_test.go

@@ -603,7 +603,7 @@ func TestGetMultipleTypeObjectsAsList(t *testing.T) {
 	}
 
 	expected := &unstructured.UnstructuredList{
-		Object: map[string]interface{}{"kind": "List", "apiVersion": "v1", "metadata": map[string]interface{}{}, "selfLink": "", "resourceVersion": ""},
+		Object: map[string]interface{}{"kind": "List", "apiVersion": "v1", "metadata": map[string]interface{}{"selfLink": "", "resourceVersion": ""}},
 		Items: []unstructured.Unstructured{
 			fn(&pods.Items[0]),
 			fn(&pods.Items[1]),