使用mini-css-extract-plugin插件

    配置：

    1. {
    2.     module: {
    3.     rules: [
    4.         {
    5.         test: /\.css$/,
    6.         use: [
    7.             MiniCssExtractPlugin.loader,
    8.             ‘css-loader’
    9.         ]
    10.         }
    11.     ]
    12.     },
    13.     plugins: [
    14.     new MiniCssExtractPlugin({
    15.         filename: ‘xxx/xxx.css’
    16.     })
    17.     ]
    18. }