touch (remotePath) {
    // if (this.enableSsh) {
    //   return new Promise((resolve, reject) => {
    //     const { client } = this
    //     const cmd = `touch "${remotePath}"`
    //     client.exec(cmd, this.getExecOpts(), err => {
    //       if (err) reject(err)
    //       else resolve(1)
    //     })
    //   })
    // }
    return this.touchFile(remotePath)
  }
touch a file

@param {String} remotePath
https://github.com/mscdex/ssh2/blob/master/SFTP.md
@return {Promise}