docs(updating): add angular toolkit upgrade to v7 upgrade guide (#2952)

Author: liamdebeasi

docs/updating/7-0.md

@@ -29,12 +29,14 @@ npm install [email protected]
 npm install @ionic/angular@7
 ```
 
-If you are using Ionic Angular Server, be sure to update that as well:
+If you are using Ionic Angular Server and Ionic Angular Toolkit, be sure to update those as well:
 
 ```shell
-npm install @ionic/angular@7 @ionic/angular-server@7
+npm install @ionic/angular@7 @ionic/angular-server@7 @ionic/angular-toolkit@9
 ```
 
+> Note: `@ionic/angular-toolkit@9` requires a minimum of Angular 15. If you are still on Angular 14, then you can skip updating to `@ionic/angular-toolkit@9`.
+
 ### React
 
 1. Ionic 7 supports React 17+. Update to the latest version of React: