nullable type syntax

Author: samsonasik

src/Listener/ForceHttps.php

@@ -39,7 +39,7 @@ public function attach(EventManagerInterface $events, $priority = 1) : void
     private function setHttpStrictTransportSecurity(
         string     $uriScheme,
         Response   $response,
-        RouteMatch $match = null
+        ?RouteMatch $match
     ) : Response {
         if ($this->isSkippedHttpStrictTransportSecurity($uriScheme, $match)) {
             return $response;