[FIX] (config) fix default subject title

Author: hugomyb

config/error-mailer.php

@@ -3,7 +3,7 @@
 return [
     'email' => [
         'recipient' => '[email protected]',
-        'subject' => 'An error was occured - ' . env('APP_NAME'),
+        'subject' => 'An error has occured - ' . env('APP_NAME'),
     ],
 
     'disabledOn' => [