code: func WithPassphrase(rootPwd, repositoryPwd string) func(cmd *icmd.Cmd) {
  	return func(cmd *icmd.Cmd) {
  		env := append(os.Environ(),
  			"DOCKER_CONTENT_TRUST_ROOT_PASSPHRASE="+rootPwd,
  			"DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE="+repositoryPwd,
  		)
  		cmd.Env = append(cmd.Env, env...)
  	}
  }
docs: //WithPassphrase sets environment variables for passphrases