fix `__dirname` and `__filename`

lessons/14-whats-next/webpack.server.config.js

@@ -20,8 +20,8 @@ module.exports = {
   }, {}),
 
   node: {
-    __filename: true,
-    __dirname: true
+    __filename: false,
+    __dirname: false
   },
 
   module: {