added Example of publishing topic

src/config/mqtt.php

@@ -13,5 +13,5 @@ return [
     'username' => env('mqtt_username',''),
     'certfile' => env('mqtt_cert_file',''),
     'port' => env('mqtt_port','1883'),
-    'debug' => env('mqtt_debug',false) //Optional Parameter to enable debuging set it to True
+    'debug' => env('mqtt_debug',false) //Optional Parameter to enable debugging set it to True
 ];