Update AttributeManager.php

Author: hailwood

src/AttributeManager.php

@@ -5,6 +5,7 @@
 use Illuminate\Database\Eloquent\Collection;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Support\Arr;
+use Illuminate\Support\Str;
 use Illuminate\View\View;
 
 class AttributeManager