Bump celery from 4.3.0 to 5.2.2

Bumps [celery](https://github.com/celery/celery) from 4.3.0 to 5.2.2.
- [Release notes](https://github.com/celery/celery/releases)
- [Changelog](https://github.com/celery/celery/blob/master/Changelog.rst)
- [Commits](celery/celery@v4.3.0...v5.2.2)

---
updated-dependencies:
- dependency-name: celery
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -1,6 +1,6 @@
 amqp==2.5.2
 billiard==3.6.1.0
-celery==4.3.0
+celery==5.2.2
 Django==2.2.24
 importlib-metadata==0.23
 kombu==4.6.6