…_queue

This commit fixes an issue where the `updates_queue.join()` method would never return.
When waiting for the `updates_queue` to get emptied, the asyncio queue implementation relies on an internal counter. This counter is incremented on each `put()` but is not automatically decremented on each `get()`.
In order to decrement the counter we need to use `updates_queue.task_done()`, as per the [docs](https://docs.python.org/3/library/asyncio-queue.html#asyncio.Queue.task_done). Since this wasn't done in pyrogram yet, there was no proper way to use the `join()` method on the updates_queue and hence wait until all updates got processed.

A workaround would be to use a while loop and check if `updates_queue.empty()` returns true. But using `join()` is just a lot cleaner and does not require a loop on our end.