Bump next from 14.2.12 to 14.2.20 in /docs/sliver-docs

Bumps [next](https://github.com/vercel/next.js) from 14.2.12 to 14.2.20.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.2.12...v14.2.20)

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

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

docs/sliver-docs/package.json

@@ -21,7 +21,7 @@
     "framer-motion": "^10.16.16",
     "fuse.js": "^7.0.0",
     "lunr": "^2.3.9",
-    "next": "^14.2.12",
+    "next": "^14.2.20",
     "next-themes": "^0.2.1",
     "react": "18.2.0",
     "react-dom": "18.2.0",