Bump celery in /{{ cookiecutter.project_name }}/app/requirements

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] <support@github.com>

{{ cookiecutter.project_name }}/app/requirements/production.txt

@@ -3,5 +3,5 @@ django-celery-beat==2.2.0
 psycopg2-binary==2.8.6
 redis==3.5.3
 kombu==5.1.0
-celery==5.0.5
+celery==5.1.0
 gunicorn==20.1.0