| identifier | A string representing the package to be added. To install a specific version of a package, use a package identifier (name@version). To install the latest compatible version of a package, use the package name only. To install a git package, specify a git url. |
AddRequest 一个 AddRequest 实例，可用于监控异步操作，并在操作完成时获取结果。
向项目添加包依赖项。