Bump celery from 4.4.3 to 4.4.4 (#340)

Bumps [celery](https://github.com/celery/celery) from 4.4.3 to 4.4.4.
- [Release notes](https://github.com/celery/celery/releases)
- [Changelog](https://github.com/celery/celery/blob/master/Changelog.rst)
- [Commits](celery/celery@4.4.3...v4.4.4)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

requirements.txt

@@ -3,5 +3,5 @@ aiohttp==3.6.2
 gidgethub==4.1.0
 cachetools==4.1.0
 redis==3.5.3
-celery==4.4.3
+celery==4.4.4
 sentry-sdk==0.14.4