sbt 0.13。x使用shell任务迁移到1.1.4

我的任务是为我的Play Framework应用程序从git中获取前端:

lazy val frontend = taskKey[Unit]("Downloads frontend")
frontend := {
  val s: TaskStreams = streams.value
  val shell: Seq[String] = if (sys.props("os.name").contains("Windows")) Seq("cmd", "/c") else Seq("bash", "-c")
  val downloadRepo: Seq[String] = shell :+ "git clone git@bitbucket.org:user/frontend.git"
  val rmJs: Seq[String] = shell :+    "rm -rf frontend/dist/js && rm -rf public/design && mkdir public/design"
  val copy: Seq[String] = shell :+    "mv frontend/dist/* public/design/"
  val rmRepo: Seq[String] = shell :+    "rm -rf frontend"
  s.log.info("Downloading frontend...")
  if((downloadRepo #&& rmJs #&& copy #&& rmRepo !) == 0) {
    s.log.success("frontend downloaded successful!")
  } else {
    throw new IllegalStateException("frontend failed!")
  }
}

它在sbt为0.13时工作良好。x、 但我想迁移到最新的版本,这给了我一个错误:

error: value #&& is not a member of Seq[String]
  if((downloadRepo #&& rmJs #&& copy #&& rmRepo !) == 0) {

我查看了新文档,但没有找到答案,如何迁移此文档?