Update Code Sandbox link

Author: bvaughn

README.md

@@ -5,7 +5,7 @@
 React components for resizable panel groups/layouts.
 
 - [View the website](https://react-resizable-panels.vercel.app/)
-- [Try it on CodeSandbox](https://codesandbox.io/s/react-resizable-panels-zf7hwd)
+- [Try it on CodeSandbox](https://codesandbox.io/p/devbox/react-resizable-panels-forked-wpkx8j)
 - [Read the documentation](https://github.com/bvaughn/react-resizable-panels/tree/main/packages/react-resizable-panels)
 - [View the changelog](https://github.com/bvaughn/react-resizable-panels/blob/main/packages/react-resizable-panels/CHANGELOG.md)