Bump next from 14.2.15 to 14.2.21 in /website

Bumps [next](https://github.com/vercel/next.js) from 14.2.15 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@v14.2.15...v14.2.21)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

website/package-lock.json

@@ -31,7 +31,7 @@
     "eslint-config-next": "13.1.6",
     "final-form": "^4.20.9",
     "lucide-react": "^0.288.0",
-    "next": "14.2.15",
+    "next": "14.2.21",
     "react": "18.2.0",
     "react-dom": "18.2.0",
     "react-final-form": "^6.5.9",