Bump celery from 4.3.1 to 5.2.2

Bumps [celery](https://github.com/celery/celery) from 4.3.1 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@v4.3.1...v5.2.2)

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

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

Author: dependabot[bot]

requirements.txt

@@ -1,4 +1,4 @@
-celery==4.3.1
+celery==5.2.2
 ckanapi==4.3
 flask-marshmallow==0.11.0 
 Flask-Migrate==2.5.3