fix README's CONTRIBUTING.md link in plugin-multiversx package (#2985)

Co-authored-by: Sayo <hi@sayo.wtf>

Author: elpulpo0

packages/plugin-multiversx/README.md

@@ -164,7 +164,7 @@ pnpm test:watch
 
 ## Contributing
 
-Contributions are welcome! Please see the [CONTRIBUTING.md](CONTRIBUTING.md) file for more information.
+Contributions are welcome! Please see the [CONTRIBUTING.md](../../CONTRIBUTING.md) file for more information.
 
 ## Credits