File _service of Package voms

<services>
  <service name="download_url">
    <param name="host">github.com</param>
    <param name="protocol">https</param>
    <param name="path">/italiangrid/voms/archive/v2.1.0-rc0.tar.gz</param>
    <param name="filename">voms-2.1.0-rc0.tar.gz</param>
  </service>
</services>