Set APIVersion:v1 for node events

pkg/exporters/k8sexporter/problemclient/problem_client.go

@@ -157,6 +157,7 @@ func getEventRecorder(c typedcorev1.CoreV1Interface, namespace, nodeName, source
 func getNodeRef(namespace, nodeName string) *v1.ObjectReference {
 	// TODO(random-liu): Get node to initialize the node reference
 	return &v1.ObjectReference{
+		APIVersion: "v1",
 		Kind:      "Node",
 		Name:      nodeName,
 		UID:       types.UID(nodeName),

pkg/exporters/k8sexporter/problemclient/problem_client_test.go

@@ -85,3 +85,13 @@ func TestEvent(t *testing.T) {
 		t.Errorf("expected event %q, got %q", expected, got)
 	}
 }
+
+func TestNodeRefHasAPIVersionV1(t *testing.T) {
+    eventNamespace := "default"
+    nodeName := "fake-node"
+    client := newFakeProblemClient(eventNamespace, nodeName)
+
+    if client.nodeRef.APIVersion != "v1" {
+        t.Errorf("expected nodeRef.APIVersion to be 'v1', got %q", client.nodeRef.APIVersion)
+    }
+}