Remove webpack config.

webpack.common.js

-const path = require('path');
-
-module.exports = {
-  entry: {
-    app: './js/app.js',
-  },
-  output: {
-    path: path.resolve(__dirname, 'dist'),
-    clean: true,
-    filename: './js/app.js',
-  },
-};

webpack.config.dev.js

-const { merge } = require('webpack-merge');
-const common = require('./webpack.common.js');
-
-module.exports = merge(common, {
-  mode: 'development',
-  devtool: 'inline-source-map',
-  devServer: {
-    liveReload: true,
-    hot: true,
-    open: true,
-    static: ['./'],
-  },
-});

webpack.config.prod.js

-const { merge } = require('webpack-merge');
-const common = require('./webpack.common.js');
-const HtmlWebpackPlugin = require('html-webpack-plugin');
-const CopyPlugin = require('copy-webpack-plugin');
-
-module.exports = merge(common, {
-  mode: 'production',
-  plugins: [
-    new HtmlWebpackPlugin({
-      template: './index.html',
-    }),
-    new CopyPlugin({
-      patterns: [
-        { from: 'img', to: 'img' },
-        { from: 'css', to: 'css' },
-        { from: 'js/vendor', to: 'js/vendor' },
-        { from: 'assets', to: 'assets' },
-        { from: 'icon.svg', to: 'icon.svg' },
-        { from: 'favicon.ico', to: 'favicon.ico' },
-        { from: 'robots.txt', to: 'robots.txt' },
-        { from: '404.html', to: '404.html' },
-        { from: 'manifest.json', to: 'manifest.json' },
-      ],
-    }),
-  ],
-});