Fix minor issues in README.md

README.md

@@ -25,9 +25,10 @@ composer require php-mqtt/laravel-client
 The package will register itself through Laravel auto discovery of packages.
 Registered will be the service provider as well as an `MQTT` facade.
 
-If you are using Lumen, You need to manually add the following code to ` bootstrap/app.php`
+If you are using Lumen, you need to manually add the following code to `bootstrap/app.php`:
+
 ```php
-$app->register(PhpMqtt\Client\MqttClientServiceProvider::class);
+$app->register(\PhpMqtt\Client\MqttClientServiceProvider::class);
 ```
 
 After installing the package, you should publish the configuration file using