Add "type": "module" to package.json

Enable ES module syntax (import/export) for the project by setting "type": "module" in package.json.

Author: Iswanna

middleware-exercise/package.json

@@ -3,6 +3,7 @@
   "version": "1.0.0",
   "description": "",
   "main": "index.js",
+  "type": "module",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },