Update django-environ requirement from ~=0.11.2 to ~=0.12.0

Updates the requirements on [django-environ](https://github.com/joke2k/django-environ) to permit the latest version.
- [Release notes](https://github.com/joke2k/django-environ/releases)
- [Changelog](https://github.com/joke2k/django-environ/blob/main/CHANGELOG.rst)
- [Commits](https://github.com/joke2k/django-environ/commits)

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

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

requirements.txt

@@ -2,7 +2,7 @@ django~=5.1.4
 pillow~=11.1.0
 django-crispy-forms~=2.3
 crispy-bulma~=0.11.0
-django-environ~=0.11.2
+django-environ~=0.12.0
 django-email-validation~=2.0.5
 django-simple-captcha~=0.6.0
 daphne~=4.1.2