Update README.md

Author: tabacitu

README.md

@@ -25,7 +25,7 @@ This package is just a user interface for [spatie/laravel-permission](https://gi
 
 ## Install
 
-0) This package assumes you've already installed [Backpack for Laravel](https://backpackforlaravel.com). If you haven't, please [install Backpack first](https://backpackforlaravel.com/docs/3.5/installation).
+0) This package assumes you've already installed [Backpack for Laravel](https://backpackforlaravel.com). If you haven't, please [install Backpack first](https://backpackforlaravel.com/docs/installation).
 
 1) In your terminal: