build(deps-dev): update django-dbbackup requirement

Updates the requirements on [django-dbbackup](https://github.com/jazzband/django-dbbackup) to permit the latest version.
- [Release notes](https://github.com/jazzband/django-dbbackup/releases)
- [Changelog](https://github.com/jazzband/django-dbbackup/blob/master/docs/changelog.rst)
- [Commits](jazzband/django-dbbackup@4.1.0...4.2.1)

---
updated-dependencies:
- dependency-name: django-dbbackup
  dependency-type: direct:development
...

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

requirements-dev.txt

@@ -2,5 +2,5 @@ Django~=5.0.7
 djangorestframework~=3.15.2
 django-filter~=24.2.0
 django-debug-toolbar~=4.4.6
-django-dbbackup~=4.1.0
+django-dbbackup~=4.2.1
 -r requirements-test.txt