Yarn option for Gesture hammerjs (#9417)

guides/getting-started.md

@@ -135,10 +135,17 @@ You can add HammerJS to your application via [npm](https://www.npmjs.com/package
 directly from your app.
 
 To install via npm, use the following command:
+
+#### NPM
 ```bash
 npm install --save hammerjs
 ```
 
+#### Yarn
+```bash
+yarn add hammerjs
+```
+
 After installing, import it on your app's entry point (e.g. `src/main.ts`).
 ```ts
 import 'hammerjs';