fix: substitui 'dates' depreciado por 'casts'

src/Subscription.php

@@ -15,13 +15,10 @@ class Subscription extends Model
      */
     protected $guarded = [];
 
-    /**
-     * The attributes that should be mutated to dates.
-     *
-     * @var array
-     */
-    protected $dates = [
-        'trial_ends_at', 'ends_at',
-        'created_at', 'updated_at',
+    protected $casts = [
+        'trial_ends_at' => 'datetime',
+        'ends_at' => 'datetime',
+        'created_at' => 'datetime',
+        'updated_at' => 'datetime',
     ];
 }