Bump django from 4.2.14 to 4.2.15 in /app

Bumps [django](https://github.com/django/django) from 4.2.14 to 4.2.15.
- [Commits](django/django@4.2.14...4.2.15)

---
updated-dependencies:
- dependency-name: django
  dependency-type: direct:production
...

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

app/requirements.txt

@@ -16,7 +16,7 @@ click-repl==0.2.0
 cryptography==41.0.1
 datapunt-keycloak-oidc @ git+https://github.com/remyvdwereld/keycloak_oidc_top.git@main
 debugpy==1.4.1
-Django==4.2.14
+Django==4.2.15
 django-axes==6.5.0
 django-celery-beat==2.6.0
 django-celery-results==2.5.1