chore(package.json): add "type" field to specify module format

package.json

@@ -2,6 +2,7 @@
   "name": "nextjs-starter-template",
   "version": "0.0.0",
   "private": true,
+  "type": "module",
   "scripts": {
     "dev": "next dev",
     "build": "next build",