Use the new STORAGES setting in Django 4.2

Use the new STORAGES setting in Django 4.2

In Django 4.2 the django.core.files.storage.get_storage_class() function
is deprecated as well as the STATICFILES_STORAGE setting in favor of
STORAGES["staticfiles"].

Use django.core.files.storage.storages to get the configured storage
class for static files instead.

For Django versions prior to 4.2 keep using the
django.core.files.storage.get_storage_class() function for backwards
compatibility.

Fixes #1758

docs/changes.rst

@@ -4,6 +4,8 @@ Change log
 Pending
 -------
 
+* Added support for the new STORAGES setting in Django 4.2 for static files.
+
 4.0.0 (2023-04-03)
 ------------------