code: func WithDockerfile(dockerfile string) func(*icmd.Cmd) func() {
  	return func(cmd *icmd.Cmd) func() {
  		cmd.Command = append(cmd.Command, "-")
  		cmd.Stdin = strings.NewReader(dockerfile)
  		return nil
  	}
  }
docs: // WithDockerfile creates / returns a CmdOperator to set the Dockerfile for a build operation