docs: def service_set_tag(path, service_name, tag):
      '''
      Change the tag of a docker-compose service
      This does not pull or up the service
      This wil re-write your yaml file. Comments will be lost. Indentation is set to 2 spaces
  
      path
          Path where the docker-compose file is stored on the server
      service_name
          Name of the service to remove
      tag
          Name of the tag (often used as version) that the service image should have
  
      CLI Example:
  
      .. code-block:: bash
  
          salt myminion dockercompose.service_create /path/where/docker-compose/stored service_name tag
      '''
      compose_result, err = __load_docker_compose(path)
      if err:
          return err
      services = compose_result['compose_content']['services']
      if service_name not in services:
          return __standardize_result(False,
                                      'Service {0} did not exists'.format(service_name),
                                      None, None)
      if 'image' not in services[service_name]:
          return __standardize_result(False,
                                      'Service {0} did not contain the variable "image"'.format(service_name),
                                      None, None)
      image = services[service_name]['image'].split(':')[0]
      services[service_name]['image'] = '{0}:{1}'.format(image, tag)
      return __dump_compose_file(path, compose_result,
                                 'Service {0} is set to tag "{1}"'.format(service_name, tag),
                                 already_existed=True)