Revert "🚀 feat: upgrade to Django 6.0"

This reverts commit b4a1b2b.

Author: matrixise

requirements/dev.txt

@@ -24,7 +24,7 @@ defusedxml==0.7.1
     # via
     #   -c requirements/main.txt
     #   py-serializable
-django==6.0
+django==5.2.9
     # via
     #   -c requirements/main.txt
     #   django-debug-toolbar

requirements/main.txt

@@ -32,7 +32,7 @@ dj-database-url==3.0.1
     # via -r requirements/main.in
 dj-static==0.0.6
     # via -r requirements/main.in
-django==6.0
+django==5.2.9
     # via
     #   -r requirements/main.in
     #   dj-database-url