Add call to action to 18 blog post (#4542)

content/blog/2022-03-29-react-v18.md

@@ -244,6 +244,10 @@ With Strict Mode in React 18, React will simulate unmounting and remounting the
 >
 > `useInsertionEffect` is intended to be used by libraries, not application code.
 
+## How to Upgrade {#how-to-upgrade}
+
+See [How to Upgrade to React 18](https://reactjs.org/blog/2022/03/08/react-18-upgrade-guide.html) for step-by-step instructions and a full list of breaking and notable changes.
+
 ## Changelog {#changelog}
 
 ### React {#react}