webpack4 使用 postcss-loader 与 autoprefixer

use: ExtractTextPlugin.extract({
    fallback: 'style-loader',
    use: [
        { loader: 'css-loader' },
        { 
            loader: 'postcss-loader',
            options: {
                plugins: [
                    require("autoprefixer")({
                        "overrideBrowserslist": [
                            "defaults",
                            "not ie < 11",
                            "last 2 versions",
                            "> 1%",
                            "iOS 7",
                            "last 3 iOS versions"
                        ]
                    })
                ]
            }
        }
    ],
    publicPath: '../'
})