Shows the current api rest version.
<response>
<header>
<item_count>1</item_count>
<request_process_time>0.001</request_process_time>
<request_result>success</request_result>
<request_result_description/>
<request_result_id>601</request_result_id>
<request_uri>[GET] version</request_uri>
<vpx_version>1.6.1</vpx_version>
</header>
<items>
<item id="1">
<version>1.6.1</version>
</item>
</items>
</response>