Route subscriber function signature

modules/salesforce_mapping_ui/src/Routing/RouteSubscriber.php

@@ -70,7 +70,7 @@ class RouteSubscriber extends RouteSubscriberBase {
   /**
    * {@inheritdoc}
    */
-  public static function getSubscribedEvents() {
+  public static function getSubscribedEvents(): array {
     $events = parent::getSubscribedEvents();
     $events[RoutingEvents::ALTER] = ['onAlterRoutes', 100];
     return $events;