Yarn1 to Yarn2

当升级yarn版本出现以下错误，需要修改yarn的代理地址

error

An unexpected error occurred: "https://github.com/yarnpkg/berry/raw/master/packages/yarnpkg-cli/bin/yarn.js: connect ECONNREFUSED 0.0.0.0:443".

# 将 {porxy_host} 和 {proxy_port} 分别替换为网络代理的服务器和端口
yarn config set proxy http://{proxy_host}:{proxy_port}
yarn config set https-proxy http://{proxy_host}:{proxy_port}

yarn set version berry