Update README.md (#4263)

Fixed a small typo.

Author: Ivaylo-Kirov

README.md

@@ -124,7 +124,7 @@ import aws_exports from './aws-exports';
 
 Amplify.configure(aws_exports);
 
-// or you don't want to install all the categories
+// or if you don't want to install all the categories
 import Amplify from '@aws-amplify/core';
 import Auth from '@aws-amplify/auth';
 import aws_exports from './aws-exports';