切换 yarn 源地址

yarn 默认的源是：https://registry.yarnpkg.com。

对于国内的程序员来说实在是太慢了，得换淘宝源地址：

PS E:\DevProjects\WebProjects\app> yarn config set registry https://registry.npm.taobao.org/
yarn config v1.22.19
success Set "registry" to "https://registry.npm.taobao.org/".
Done in 0.07s.

获取源地址：

PS E:\DevProjects\WebProjects\app> yarn config get registry
https://registry.npm.taobao.org/