File _service of Package stunnel-image

<services>
  <service mode="buildtime" name="docker_label_helper"/>
  <service mode="buildtime" name="kiwi_metainfo_helper"/>
  <service mode="buildtime" name="replace_using_package_version">
    <param name="file">Dockerfile</param>
    <param name="regex">%%stunnel_re%%</param>
    <param name="package">stunnel</param>
  </service>
</services>