Bump @liveblocks/react from 2.20.0 to 2.21.0

Bumps [@liveblocks/react](https://github.com/liveblocks/liveblocks/tree/HEAD/packages/liveblocks-react) from 2.20.0 to 2.21.0.
- [Release notes](https://github.com/liveblocks/liveblocks/releases)
- [Changelog](https://github.com/liveblocks/liveblocks/blob/main/CHANGELOG.md)
- [Commits](https://github.com/liveblocks/liveblocks/commits/v2.21.0/packages/liveblocks-react)

---
updated-dependencies:
- dependency-name: "@liveblocks/react"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -23,7 +23,7 @@
     "@hello-pangea/dnd": "^18.0.1",
     "@liveblocks/client": "^2.20.0",
     "@liveblocks/node": "^2.20.0",
-    "@liveblocks/react": "^2.20.0",
+    "@liveblocks/react": "^2.21.0",
     "@mdx-js/loader": "^3.1.0",
     "@mdx-js/react": "^3.1.0",
     "@next/mdx": "^15.2.3",