docs: update README to be more clear

Author: eddyerburgh

README.md

@@ -10,9 +10,7 @@ npm install --save-dev jest-vue
 
 ## Setup
 
-Note: this step is only required if you are using babel-jest with additional code preprocessors.
-
-To define jest-vue as a transformer for your .vue code, map .vue files to the babel-jest module.
+To define jest-vue as a transformer for your .vue files, you need to map .vue files to the jest-vue module.
 
 ```
 "transform": {