docs: demo for using LiquidJS with webpack

demo/webpack/webpack.config.js

@@ -0,0 +1,15 @@
+const path = require('path');
+const { ContextReplacementPlugin } = require('webpack')
+
+module.exports = {
+  entry: './src/index.js',
+  mode: 'development',
+  target: 'node',
+  plugins: [
+    new ContextReplacementPlugin(/liquidjs/)
+  ],
+  output: {
+    filename: 'index.js',
+    path: path.resolve(__dirname, 'dist'),
+  },
+};