[Dependencies] Support Django 5.0

[rafaelurben]

https://docs.djangoproject.com/en/5.0/releases/5.0/#miscellaneous

Possibly important changes:

• AdminSite.site_header is now rendered in a ´div´ tag instead of ´h1´. Screen reader users rely on heading elements for navigation within a page. Having two ´h1´ elements was confusing and the site header wasn’t helpful as it is repeated on all pages.
• In order to improve accessibility, the admin’s main content area and header content area are now rendered in a ´main´ and ´header´ tag instead of ´div´.

<h1 id="site-name"> => <div id="site-name">

Update: Seems to work without changing. Might change later when dropping 4.2 support.

[rafaelurben]

Colors in the admin have changed in Django 5.0. Needs more investigating...

[rafaelurben]

Added fixes in https://github.com/rafaelurben/django-kmuhelper/commit/191b9e73145e12e52a4132838b86054b51e228d1 and https://github.com/rafaelurben/django-kmuhelper/commit/d9a267e09bf66f9cae6583813c4a23039b3cb235