yarn 錯誤There appears to be trouble with your network connection. Retrying

yarn 錯誤There appears to be trouble with your network connection. Retrying…

原因：yarn超時

解決途徑：
1、安裝好後更換淘寶鏡像

yarn config set registry https://registry.npm.taobao.org

yarn config delete proxy
npm config rm proxy
npm config rm https-proxy

npm 超時

安裝cnpm鏡像
npm install -g cnpm --registry=https://registry.npm.taobao.org
使用代理registry
npm config set registry https://registry.npm.taobao.org