Add public keyword to methods

[MAILPOET-2413]

lib/DynamicSegments/FreePluginConnectors/SubscribersListingsHandlerFactory.php

@@ -8,7 +8,7 @@ use MailPoet\Models\Segment;
 
 class SubscribersListingsHandlerFactory {
 
-  function get(Segment $segment, $data) {
+  public function get(Segment $segment, $data) {
     if ($segment->type === DynamicSegment::TYPE_DYNAMIC) {
       $listing = new Handler();
       return $listing_data = $listing->get('\MailPoet\Models\SubscribersInDynamicSegment', $data);