show optional dependency

Author: brianzinn

README.md

@@ -9,6 +9,7 @@ Add babylonjs dependencies:
 yarn add react-babylonjs
 yarn add @babylonjs/core
 yarn add @babylonjs/gui
+# loaders are optional
 yarn add @babylonjs/loaders
 ```
 
@@ -24,4 +25,4 @@ Open [http://localhost:3000](http://localhost:3000) to view it in the browser.
 The page will reload if you make edits.<br>
 You will also see any lint errors in the console.
 
-View [live demo](https://brianzinn.github.io/create-react-app-typescript-babylonjs/)
+View [live demo](https://brianzinn.github.io/create-react-app-typescript-babylonjs/)