chore: update readme

Author: joshuaellis

README.md

@@ -20,8 +20,6 @@ This library represents a modern approach to animation. It is very much inspired
 
 More info about the project can be found [here](https://www.react-spring.io).
 
-For info specific to v9 can be found [here](https://aleclarson.github.io/react-spring/v9/).
-
 Examples and tutorials can be found [here](https://www.react-spring.io/docs/hooks/basics).
 
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