[Backend Dependencies Update] Update celery to 4.4.1

[pyup-bot]

This PR updates celery from 4.3.0 to 4.4.1.

Changelog

4.4.0

=======
:release-date: 2019-12-16 9.45 A.M UTC+6:00
:release-by: Asif Saif Uddin

- This version is officially supported on CPython 2.7,
3.5, 3.6, 3.7 & 3.8 and is also supported on PyPy2 & PyPy3.
- Kombu 4.6.7
- Task class definitions can have retry attributes (5869)

4.4.0rc5

========
:release-date: 2019-12-07 21.05 A.M UTC+6:00
:release-by: Asif Saif Uddin

- Kombu 4.6.7
- Events bootstep disabled if no events (5807)
- SQS - Reject on failure (5843)
- Add a concurrency model with ThreadPoolExecutor (5099)
- Add auto expiry for DynamoDB backend (5805)
- Store extending result in all backends (5661)
- Fix a race condition when publishing a very large chord header (5850)
- Improve docs and test matrix

4.4.0rc4

========
:release-date: 2019-11-11 00.45 A.M UTC+6:00
:release-by: Asif Saif Uddin

- Kombu 4.6.6
- Py-AMQP 2.5.2
- Python 3.8
- Numerious bug fixes
- PyPy 7.2

4.4.0rc3

========
:release-date: 2019-08-14 23.00 P.M UTC+6:00
:release-by: Asif Saif Uddin

- Kombu 4.6.4
- Billiard 3.6.1
- Py-AMQP 2.5.1
- Avoid serializing datetime (5606)
- Fix: (group() | group()) not equals single group (5574)
- Revert "Broker connection uses the heartbeat setting from app config.
- Additional file descriptor safety checks.
- fixed call for null args (5631)
- Added generic path for cache backend.
- Fix Nested group(chain(group)) fails (5638)
- Use self.run() when overriding __call__ (5652)
- Fix termination of asyncloop (5671)
- Fix migrate task to work with both v1 and v2 of the message protocol.
- Updating task_routes config during runtime now have effect.

4.4.0rc2

========
:release-date: 2019-06-15 4:00 A.M UTC+6:00
:release-by: Asif Saif Uddin

- Many bugs and regressions fixed.
- Kombu 4.6.3

4.4.0rc1

========
:release-date: 2019-06-06 1:00 P.M UTC+6:00
:release-by: Asif Saif Uddin


- Python 3.4 drop

- Kombu 4.6.1

- Replace deprecated PyMongo methods usage (5443)

- Pass task request when calling update_state (5474)

- Fix bug in remaining time calculation in case of DST time change (5411)

- Fix missing task name when requesting extended result (5439)

- Fix `collections` import issue on Python 2.7 (5428)

- handle `AttributeError` in base backend exception deserializer (5435)

- Make `AsynPool`'s `proc_alive_timeout` configurable (5476)

- AMQP Support for extended result (5495)

- Fix SQL Alchemy results backend to work with extended result (5498)

- Fix restoring of exceptions with required param (5500)

- Django: Re-raise exception if `ImportError` not caused by missing tasks
module (5211)

- Django: fixed a regression putting DB connections in invalid state when
`CONN_MAX_AGE != 0` (5515)

- Fixed `OSError` leading to lost connection to broker (4457)

- Fixed an issue with inspect API unable get details of Request

- Fix mogodb backend authentication (5527)

- Change column type for Extended Task Meta args/kwargs to LargeBinary

- Handle http_auth in Elasticsearch backend results (5545)

- Fix task serializer being ignored with `task_always_eager=True` (5549)

- Fix `task.replace` to work in `.apply() as well as `.apply_async()` (5540)

- Fix sending of `worker_process_init` signal for solo worker (5562)

- Fix exception message upacking (5565)

- Add delay parameter function to beat_schedule (5558)

- Multiple documentation updates

Links

• PyPI: https://pypi.org/project/celery
• Changelog: https://pyup.io/changelogs/celery/
• Homepage: http://celeryproject.org
• Docs: https://pythonhosted.org/celery/

[pyup-bot]

Closing this in favor of #815