Bump celery from 5.0.5 to 5.1.0 (#460)

Bumps [celery](https://github.com/celery/celery) from 5.0.5 to 5.1.0.
- [Release notes](https://github.com/celery/celery/releases)
- [Changelog](https://github.com/celery/celery/blob/master/Changelog.rst)
- [Commits](celery/celery@v5.0.5...v5.1.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Mariatta Wijaya <[email protected]>

Author: dependabot[bot]

requirements.txt

@@ -3,5 +3,5 @@ aiohttp==3.7.4.post0
 gidgethub==5.0.1
 cachetools==4.2.2
 redis==3.5.3
-celery==5.0.5
+celery==5.1.0
 sentry-sdk==1.1.0