Graph API: add 'categories' and 'Start Date' property for Microsoft To Do tasks

I'm reading a task with the Graph API for To Do like this:

GET /me/todo/lists/{todoTaskListId}/tasks

I only get some basic properties (e.g. body, dueDate, status, ...) of a task, but some essentials are missing like category or start date. 

Please add those properties to the API.