Bump celery from 4.2.1 to 5.2.2

Bumps [celery](https://github.com/celery/celery) from 4.2.1 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@v4.2.1...v5.2.2)

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

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

Author: dependabot[bot]

setup.py

@@ -41,7 +41,7 @@
         'botocore==1.10.79',
         'cairocffi==0.9.0',
         'CairoSVG==2.1.3',
-        'celery==4.2.1',
+        'celery==5.2.2',
         'certifi==2018.8.13',
         'cffi==1.13.2',
         'cryptography==2.3.1',