fix connection.close raising errors on python 3.8

Author: ikkez

anki_vector/connection.py

@@ -611,6 +611,9 @@ async def play_animation():
         """
         if self._control_events:
             self._control_events.shutdown()
+            # need to wait until all Futures were cancled before going on,
+            # otherwise python 3.8+ will raise alot of CancelledErrors and
+            time.sleep(2)
         if self._control_stream_task:
             self._control_stream_task.cancel()
             self.run_coroutine(self._control_stream_task).result()