[back] sec: upgrade Django to 4.1.12 (from 4.1.11)

[GresilleSiffle]

Description

Fix:

• CVE-2023-43665

See:

• https://www.djangoproject.com/weblog/2023/oct/04/security-releases/

Checklist

• I added the related issue(s) id in the related issues section (if any)
  • if not, delete the related issues section
• I described my changes and my decisions in the PR description
• I read the development guidelines of the CONTRIBUTING.md
• The tests pass and have been updated if relevant
• The code quality check pass

[GresilleSiffle]

Thank you ;)