Laravel: Stop calling deprecated fire() method

This has been deprecated and removed from the contract for a long time,
and it will be completely dropped in v5.8, our next upgrade target.

src/helpers.php

@@ -90,6 +90,6 @@ if (! function_exists('event')) {
      */
     function event($event, $payload = [], $halt = false)
     {
-        return app('events')->fire($event, $payload, $halt);
+        return app('events')->dispatch($event, $payload, $halt);
     }
 }