Bump celery from 4.4.2 to 4.4.3

Bumps [celery](https://github.com/celery/celery) from 4.4.2 to 4.4.3.
- [Release notes](https://github.com/celery/celery/releases)
- [Changelog](https://github.com/celery/celery/blob/master/Changelog.rst)
- [Commits](https://github.com/celery/celery/compare/4.4.2...4.4.3)

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

setup.py

@@ -39,7 +39,7 @@ setup(
         'Flask-WTF==0.14.3',
         'Flask-Caching==1.8.0',
         'geopy==1.22.0',
-        'celery==4.4.2',
+        'celery==4.4.3',
         'redis==3.5.2',
         'aerofiles==1.0.0',
         'geoalchemy2==0.8.3',