Add deprecation notice

Author: m1guelpf

lib/Github/Api/Integrations.php

@@ -2,8 +2,10 @@
 
 namespace Github\Api;
 
+@trigger_error('The '.__NAMESPACE__.'\Integrations class is deprecated. Use the '.__NAMESPACE__.'\Apps class instead.', E_USER_DEPRECATED);
+
 /**
- * @deprecated
+ * @deprecated Use the Apps class
  * @link   https://developer.github.com/v3/apps/
  * @author Nils Adermann <naderman@naderman.de>
  */