add env variable

Author: taylorotwell

config/logging.php

@@ -73,6 +73,7 @@
         'stderr' => [
             'driver' => 'monolog',
             'handler' => StreamHandler::class,
+            'formatter' => env('LOG_STDERR_FORMATTER'),
             'with' => [
                 'stream' => 'php://stderr',
             ],