Fix deprecated import
Fix deprecated import

Fixes deprecation message in Python 3.3+ and fixes compatibility with PYthon 3.10

controlcenter\widgets\core.py:88: DeprecationWarning: Using or importing the ABCs from 'collections' instead of from 'collections.abc' is deprecated since Python 3.3, and in 3.10 it will stop working
byashimov/django-controlcenter,byashimov/django-controlcenter,byashimov/django-controlcenter