fix: good practices - spelling mistake

subjects/good-practices/README.md

@@ -84,7 +84,7 @@ It is possible to remove painting by adding a layer:
   }
 ```
 
-By creating a new layer you can remove painting, but "there is always a tradeoff". If we add to much layers it will increase the **composition** and **update tree**. In conclusion you must promote a new layer only if you now you are going to use it. Performance is the key to a good animation. "Performance is the art of avoiding work".
+By creating a new layer you can remove painting, but "there is always a tradeoff". If we add to much layers it will increase the **composition** and **update tree**. In conclusion you must promote a new layer only if you know you are going to use it. Performance is the key to a good animation. "Performance is the art of avoiding work".
 
 ### UI/UX