Bump next from 14.1.3 to 14.2.21 in /examples/nextjs-scheduler

Bumps [next](https://github.com/vercel/next.js) from 14.1.3 to 14.2.21.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.1.3...v14.2.21)

---
updated-dependencies:
- dependency-name: next
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

examples/nextjs-scheduler/package.json

@@ -9,7 +9,7 @@
     "lint": "next lint"
   },
   "dependencies": {
-    "next": "14.1.3",
+    "next": "14.2.21",
     "react": "18.2.0",
     "react-calendar": "^4.6.0",
     "react-dom": "18.2.0",