Use the new API notation for external URL ('link')

lib/inventree/model.dart

@@ -45,7 +45,8 @@ class InvenTreeModel {
 
   int get parentId => jsondata['parent'] ?? -1;
 
-  String get link => jsondata['URL'] ?? '';
+  // Legacy API provided external link as "URL", while newer API uses "link"
+  String get link => jsondata['link'] ?? jsondata['URL'] ?? '';
 
   // Create a new object from JSON data (not a constructor!)
   InvenTreeModel createFromJson(Map<String, dynamic> json) {

lib/widget/part_display.dart

@@ -104,7 +104,7 @@ class _PartDisplayState extends State<PartDisplayWidget> {
     tiles.add(
       Card(
         child: ListTile(
-          title: Text("In Stock"),
+          title: Text("Stock"),
           leading: FaIcon(FontAwesomeIcons.boxes),
           trailing: Text("${part.inStock}"),
           onTap: null,