use pointer for configchanges struct

server/models/models.go

@@ -58,8 +58,8 @@ type CloudEventReceived struct {
 					Value string `json:"Value"`
 				} `json:"Vm"`
 			} `json:"Vm"`
-			ConfigSpec    *json.RawMessage      `json:"configSpec"`
-			ConfigChanges ConfigChangesReceived `json:"configChanges"`
+			ConfigSpec    *json.RawMessage       `json:"configSpec"`
+			ConfigChanges *ConfigChangesReceived `json:"configChanges"`
 		} `json:"data"`
 	} `json:"cloudEvent"`
 }