Fix example errors (Azure#14581)

Author: dpokluda

specification/deviceupdate/data-plane/Microsoft.DeviceUpdate/preview/2020-09-01/examples/Devices_CreateOrUpdateGroup.json

@@ -2,12 +2,12 @@
   "parameters": {
     "accountEndpoint": "contoso.api.adu.microsoft.com",
     "instanceId": "blue",
-    "groupId": "group1",
+    "groupId": "MyGroup",
     "group": {
       "groupId": "MyGroup",
       "groupType": "IoTHubTag",
       "tags": [
-        "MyAduGroup"
+        "MyGroup"
       ],
       "createdDateTime": "2020-07-01T12:13:14.0000000Z"
     }
@@ -18,7 +18,7 @@
         "groupId": "MyGroup",
         "groupType": "IoTHubTag",
         "tags": [
-          "MyAduGroup"
+          "MyGroup"
         ],
         "createdDateTime": "2020-07-01T12:13:14.0000000Z"
       }