set mode: production to silence webpack warning

webpack.config.js

@@ -1,10 +1,11 @@
 const path = require('path');
 
 module.exports = {
-  target: 'node',
-  entry: './index.js',
-  output: {
-    filename: 'index.js',
-    path: path.resolve(__dirname, 'dist'),
-  },
+    target: 'node',
+    entry: './index.js',
+    mode: 'production',
+    output: {
+        filename: 'index.js',
+        path: path.resolve(__dirname, 'dist'),
+    },
 };