Changed API to 1.6.8.0

Changed API version to 1.6.8.0 as this request isn't implemented in 1.6.3.0

Author: joverthegrey

src/DALTCORE/Plesk/ListIPAddresses.php

@@ -8,7 +8,7 @@ class ListIPAddresses extends BaseRequest
      */
     public $xml_packet = <<<EOT
 <?xml version="1.0"?>
-<packet version="1.6.3.0">
+<packet version="1.6.8.0">
 <ip>
 	<get/>
 </ip>