chore(deps): bump celery from 4.4.0 to 5.2.2 in /requirements

Bumps [celery](https://github.com/celery/celery) from 4.4.0 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@4.4.0...v5.2.2)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements/base.txt

@@ -2,7 +2,7 @@ bs4
 ccxt
 cryptocompare==0.6
 cryptography==2.3
-celery==4.4.0
+celery==5.2.2
 django-celery-beat==1.1.1
 django==2.2.24
 django-csp==3.7