deprecate Version constant

Author: webmaster777

src/MessageBird/Client.php

@@ -16,7 +16,10 @@ class Client
     const CONVERSATIONSAPI_ENDPOINT = 'https://conversations.messagebird.com/v1';
     const VOICEAPI_ENDPOINT = 'https://voice.messagebird.com';
 
-    const CLIENT_VERSION = '1.14.1';
+    /**
+     * @deprecated 1.15.0
+     */
+    const CLIENT_VERSION = 'DEPRECATED';
     const PACKAGE_NAME = 'messagebird/php-rest-api';
 
     /**