报错：invalid "instanceof" keyword value Promise 或者Error: Cannot find module 'webpack-cli/bin/config-yargs'
webpack 和webpack-dev-server的版本不兼容
重新安装和webpack 兼容的webpack-dev-server
自测可行版本：
webpack 3.5.5 npm install webpack@3.5.5 -g
webpack-dev-server 2.11.2 npm install webpack-dev-server@2.11.2