fix(premium-subs): clear subscription list cache after insert

fixes #430

modules/PremiumPodcasts/Models/SubscriptionModel.php

@@ -54,6 +54,11 @@ class SubscriptionModel extends Model
      */
     protected $useTimestamps = true;
 
+    /**
+     * @var string[]
+     */
+    protected $afterInsert = ['clearCache'];
+
     /**
      * @var string[]
      */