AVA 1.0 has some breaking changes which cause many test cases to fail.
Until those can be fixed, this change keeps the AVA version in the 0.x
range.

Currently only supported for concurrency === 1

Support adding tasks dynamically, after tasks have started running

    This adds a new 'onComplete' optional callback for each task. The
    callback gets called when the task is finished, either successfully or
    if it throws an error. In the success case, this gives the user an
    opportunity to perform an action before moving onto the next task.
    In the error case it gives an opportunity to inspect the error and
    modify or ignore it before moving on. This is particularly useful
    when using Listr with completely asynchronous or concurrent task
    operations.

Add TypeScript types and task onComplete callback