add Fulfillment as child resource of FulfillmentOrder

Author: jeroendelau

lib/FulfillmentOrder.php

@@ -1,8 +1,5 @@
 <?php
 /**
- * Created by PhpStorm.
- * @author Mark Solly <mark@solly.com.au>
- * Created at 5/21/21 11:27 AM UTC+10:00
  *
  * @see https://shopify.dev/docs/admin-api/rest/reference/shipping-and-fulfillment/fulfillmentorder Shopify API Reference for Fulfillment Order
  */
@@ -15,6 +12,7 @@
  * FulfillmentOrder -> Child Resources
  * --------------------------------------------------------------------------
  * @property-read FulfillmentRequest $FulfillmentRequest
+ * @property-read Fulfillment $Fulfillment
  *
  * --------------------------------------------------------------------------
  * Fulfillment -> Custom actions
@@ -38,7 +36,8 @@ class FulfillmentOrder extends ShopifyResource
      * @inheritDoc
      */
     protected $childResource = array (
-        'FulfillmentRequest'
+        'FulfillmentRequest',
+        'Fulfillment'
     );
 
     /**