Refresh task queue first before get task from queue

This allows relinquishing control to the event loop to ensure requeueing
coroutines have the chance to get run before another task is fetched
from the queue.

src/kiwipy/rmq/tasks.py

@@ -119,6 +119,9 @@ async def next_task(self,
         raises:
             kiwipy.exceptions.QueueEmpty: When the queue has no tasks within the timeout
         """
+        # relinquish so that if there is requeue coroutines, they are run first and task queue get updated
+        await asyncio.sleep(0)
+
         try:
             message = await self._task_queue.get(no_ack=no_ack, fail=fail, timeout=timeout)
         except aio_pika.exceptions.QueueEmpty as exc: