Adds or updates a TaskAssignee to a Task. If the TaskAssignee is already assigned to the Task, update their allocation. If the TaskAssignee is not yet assigned to the Task, assign them and set their allocation level to the correct amount.
A TaskAssignee is an assignment of a Resource to a Task. You can assign multiple Resources to a Task and designate what proportion of their time will be allocated to this Task.
See ChangeSetStatusDto for the complete data definition.