Bump django-model-utils from 4.5.1 to 5.0.0 in /backend

Bumps [django-model-utils](https://github.com/jazzband/django-model-utils) from 4.5.1 to 5.0.0.
- [Release notes](https://github.com/jazzband/django-model-utils/releases)
- [Changelog](https://github.com/jazzband/django-model-utils/blob/master/CHANGES.rst)
- [Commits](jazzband/django-model-utils@4.5.1...5.0.0)

---
updated-dependencies:
- dependency-name: django-model-utils
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

backend/pyproject.toml

@@ -46,7 +46,7 @@ requires-python = "<3.13,>=3.11"
 dependencies = [
     "django==5.1.4",
     "django-environ==0.10.0",
-    "django-model-utils==4.5.1",
+    "django-model-utils==5.0.0",
     "django-timezone-field==7.0",
     "certifi==2024.7.4",
     "chardet==5.2.0",