Indicate that create react app 4.0 has been released (#3356)

* Indicate that create react app 4.0 has been released

* Update content/blog/2020-09-22-introducing-the-new-jsx-transform.md

Co-authored-by: Sebastian Silbermann <silbermann.sebastian@gmail.com>

content/blog/2020-09-22-introducing-the-new-jsx-transform.md

@@ -99,7 +99,7 @@ Since the new JSX transform doesn't require React to be in scope, [we've also pr
 
 ### Create React App {#create-react-app}
 
-Create React App support [has been added](https://github.com/facebook/create-react-app/pull/9645) and will be available in the [upcoming v4.0 release](https://gist.github.com/iansu/4fab7a9bfa5fa6ebc87a908c62f5340b) which is currently in beta testing.
+Create React App [4.0.0](https://github.com/facebook/create-react-app/releases/tag/v4.0.0)+ uses the new transform for compatible React versions.
 
 ### Next.js {#nextjs}