Bump celery from 3.1.17 to 5.2.2

Bumps [celery](https://github.com/celery/celery) from 3.1.17 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@v3.1.17...v5.2.2)

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

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

requirements.txt

@@ -123,7 +123,7 @@ anyjson==0.3.3
 audioread==1.0.3
 billiard==3.3.0.19
 bleach==3.3.0
-celery==3.1.17
+celery==5.2.2
 chardet==2.3.0
 cssselect==0.9.1
 django-bleach==0.5.2