Fix for Settings element not Parsing

The PayrollAU\Settings endpoint is 1D the same as Payslip / Payitems, or at least editing it in the way I have makes it work properly.

Sorry I don't know how to check if it works with \PayrollUS or \Assets or if there are other \Settings objects to look out for

src/XeroPHP/Remote/Response.php

@@ -323,6 +323,7 @@ public function parseXML()
                     break;
                 case 'Payslip':
                 case 'PayItems':
+                case 'Settings':
                     // some xero endpoints are 1D so we can parse them straight away
                     $this->elements[] = Helpers::XMLToArray($root_child);