message: Stop using deprecated task API
diff: @@ -25,8 +25,8 @@ import backoff
  import msgpack
  import pyarrow as pa
  import simplejson as json
  +from celery import Task
  from celery.exceptions import SoftTimeLimitExceeded
  -from celery.task.base import Task
  from flask_babel import lazy_gettext as _
  from sqlalchemy.orm import Session
  from werkzeug.local import LocalProxy
  