code: func dispatchMaintainer(d dispatchRequest, c *instructions.MaintainerCommand) error {
  
  	d.state.maintainer = c.Maintainer
  	return d.builder.commit(d.state, "MAINTAINER "+c.Maintainer)
  }
docs: // MAINTAINER some text <maybe@an.email.address>
  //
  // Sets the maintainer metadata.