docs(sources/companion-plugins/google-drive): adds information on req…

…uired app scopes. (#222)

Co-authored-by: Antoine du Hamel <duhamelantoine1995@gmail.com>

docs/sources/companion-plugins/google-drive.mdx

@@ -94,6 +94,12 @@ Create a project for your app if you don’t have one yet.
 - On the project’s dashboard,
   [enable the Google Drive API](https://developers.google.com/drive/api/v3/enable-drive-api).
 - [Set up OAuth authorization](https://developers.google.com/drive/api/v3/about-auth).
+  - Under scopes, add the `https://www.googleapis.com/auth/drive.readonly` Drive
+    API scope.
+  - Due to this being a sensitive scope, your app must complete Google’s OAuth
+    app verification before being granted access. See
+    [OAuth App Verification Help Center](https://support.google.com/cloud/answer/13463073)
+    for more information.
 
 The app page has a `"Redirect URIs"` field. Here, add: