📝 (GettingStarted) add peer dependencie installation instruction

Author: tpucci

docs/GettingStarted.mdx

@@ -11,6 +11,7 @@ React-gondola needs the following dependencies; if you do not have those install
 | Dependencie name | Yarn Installation command | NPM Installation command |
 | :--------------: | :-----------------------: | :----------------------: |
 |      `mobx`      |      `yarn add mobx`      |       `npm i mobx`       |
+|   `mobx-react`   |   `yarn add mobx-react`   |    `npm i mobx-react`    |
 |      `rxjs`      |      `yarn add rxjs`      |       `npm i rxjs`       |
 
 Then, install React-Gondola with: