Remove compat layer for Django 1.x

favicon/models.py

+from io import BytesIO
 import sys
 
 from PIL import Image
-from compat import BytesIO
 from django.conf import settings
 from django.core.files.storage import default_storage as storage
 from django.core.files.uploadedfile import InMemoryUploadedFile

requirements.txt

 django
-django-compat
 pillow