Add a mention of upgrading history. Closes #8232

Author: timdorr

docs/upgrading/v5.md

@@ -147,6 +147,14 @@ $ npm install react-router-dom@next
 $ npm install react-router-native@next
 ```
 
+> **Note:** If you also have `history` as a dependency in your `package.json`, you will also need to upgrade it to v5:
+>
+> ```bash
+> $ npm install history@5
+> ```
+>
+> However, we recommend you remove it as a direct dependency, as we now wrap most of its APIs with hooks for better support of React Suspense.
+
 ### Upgrade all `<Switch>` elements to `<Routes>`
 
 React Router v6 introduces a `Routes` component that is kind of like `Switch`, but a lot more powerful. The main advantages of `Routes` over `Switch` are: