[Maintenance] Remove assets installation step from README

Author: Rafikooo

README.md

@@ -51,14 +51,6 @@ From Administrator's point of view, every Refund request results in creating two
     bin/console doctrine:migrations:migrate
     ```
 
-1. Install assets:
-
-   Add the following line to your `assets/admin/entrypoint.js` file:
-
-    ```js
-   import '../../vendor/sylius/refund-plugin/assets/entrypoint';
-    ```
-
 1. Run `yarn encore dev` or `yarn encore production`
 
 1. Default configuration assumes enabled PDF file generator. If you don't want to use that feature change your app configuration: