added css minimizer to webpack

webpack.config.js

@@ -1,5 +1,7 @@
 const path = require('path');
 const MiniCssExtractPlugin = require('mini-css-extract-plugin');
+const CssMinimizerPlugin = require("css-minimizer-webpack-plugin");
+
 
 module.exports = {
     entry: './src/js/app.js',
@@ -15,6 +17,11 @@ module.exports = {
             },
         ],
     },
+    optimization: {
+        minimizer: [
+            new CssMinimizerPlugin(),
+        ],
+    },
     plugins: [
         new MiniCssExtractPlugin({
             filename: 'styles.css',