add stderr example

config/logging.php

@@ -1,5 +1,7 @@
 <?php
 
+use Monolog\Handler\StreamHandler;
+
 return [
 
     /*
@@ -56,6 +58,14 @@ return [
             'level' => 'critical',
         ],
 
+        'stderr' => [
+            'driver' => 'monolog',
+            'handler' => StreamHandler::class,
+            'with' => [
+                'stream' => 'php://stderr',
+            ],
+        ],
+
         'syslog' => [
             'driver' => 'syslog',
             'level' => 'debug',