Added @ react-navigation/stack package (react-navigation#739)

Added @ react-navigation/stack package in the compatibility documentation.

Author: dougmbarcellos

versioned_docs/version-5.x/compatibility.md

@@ -11,7 +11,7 @@ React Navigation 5 has a completely new API, so our old code using React Navigat
 To use the compatibility layer, we need to install [`@react-navigation/compat`](https://github.com/react-navigation/react-navigation/tree/master/packages/compat):
 
 ```bash npm2yarn
-npm install @react-navigation/native @react-navigation/compat
+npm install @react-navigation/native @react-navigation/compat @react-navigation/stack
 ```
 
 Then we can make minimal changes in our code to use it: