Log Message:
py-django: updated to 1.11.12

Django 1.11.12:
Bugfixes:
Fixed a regression in Django 1.11.8 where combining two annotated values_list() \ 
querysets with union(), difference(), or intersection() crashed due to \ 
mismatching columns.
Fixed a regression in Django 1.11 where an empty choice could be initially \ 
selected for the SelectMultiple and CheckboxSelectMultiple widgets