Bump django-celery-beat from 2.3.0 to 2.4.0

Bumps [django-celery-beat](https://github.com/celery/django-celery-beat) from 2.3.0 to 2.4.0.
- [Release notes](https://github.com/celery/django-celery-beat/releases)
- [Changelog](https://github.com/celery/django-celery-beat/blob/master/Changelog)
- [Commits](celery/django-celery-beat@v2.3.0...v2.4.0)

---
updated-dependencies:
- dependency-name: django-celery-beat
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

pyproject.toml

@@ -36,7 +36,7 @@ cloudflare = "^2"
 dj-database-url = "1.0.0"
 django = "^3.2"
 django-anymail = "^8.3"
-django-celery-beat = "2.3.0"
+django-celery-beat = "2.4.0"
 django-csp = "^3.7"
 django-extensions = "3.2.1"
 django-filter = "^22.1"