Description:
------------
The `xmlrpc_encode_request` function ignores the value of `encoding` and `escaping` output options if users do not use a explicit value for the `version` option when calling.

Note: The xmlrpc extension must be loaded first.

Test script:
---------------
<?php

$params = 'Lê Trung Hiếu';

echo xmlrpc_encode_request('foo', $params, ['encoding' => 'UTF-8', 'escaping' => 'markup']);

Expected result:
----------------
<?xml version="1.0" encoding="UTF-8"?>
<methodCall>
<methodName>foo</methodName>
<params>
 <param>
  <value>
   <string>Lê Trung Hiếu</string>
  </value>
 </param>
</params>
</methodCall>


Actual result:
--------------
<?xml version="1.0" encoding="iso-8859-1"?>
<methodCall>
<methodName>foo</methodName>
<params>
 <param>
  <value>
   <string>L&#195;&#170; Trung Hi&#225;&#186;&#191;u</string>
  </value>
 </param>
</params>
</methodCall>