fix: upgrade @types/node from 18.11.18 to 18.18.9

Snyk has created this PR to upgrade @types/node from 18.11.18 to 18.18.9.

See this package in npm:
https://www.npmjs.com/package/@types/node

See this project in Snyk:
https://app.snyk.io/org/sammyfilly/project/5c60a725-830a-4d3c-9c83-caecf941fa5a?utm_source=github&utm_medium=referral&page=upgrade-pr

examples/app-dir-mdx/package.json

@@ -8,7 +8,7 @@
   "dependencies": {
     "@next/mdx": "latest",
     "@types/mdx": "2.0.3",
-    "@types/node": "18.11.18",
+    "@types/node": "18.18.9",
     "@types/react": "18.0.27",
     "@types/react-dom": "18.0.10",
     "next": "latest",