fix(docs): Update README.md (#31)

Fixed the link to the V2 branch

Author: pierrenel

README.md

@@ -1,7 +1,7 @@
  Sanity Dashboard
 
 > This is a **Sanity Studio v3** plugin.
-> For the v2 version, please refer to the [v2-branch](https://github.com/sanity-io/sanity/tree/next/packages/%40sanity/dashboard).
+> For the v2 version, please refer to the [v2-branch](https://github.com/sanity-io/dashboard/tree/studio-v2).
 
 ## What is it?