'admin_static' is not a registered tag library

[Jakejamesreid]

I get the following error when extending UnsavedChangesAdmin
'admin_static' is not a registered tag library. Must be one of:
admin_list
admin_modify
admin_urls
cache
i18n
l10n
log
static
tz

Fix was to use {% load static %} instead of {% load admin_static %} in the change_form.html file.

Found solution here:
jazzband/django-constance#366