misc: remove usage of django.utils.six (#63685)

chrono/manager/forms.py

@@ -19,6 +19,7 @@ import copy
 import csv
 import datetime
 from collections import defaultdict
+from io import StringIO
 from operator import itemgetter
 
 import django_filters
@@ -32,7 +33,6 @@ from django.db.models import DurationField, ExpressionWrapper, F
 from django.forms import ValidationError, formset_factory
 from django.utils.encoding import force_text
 from django.utils.formats import date_format
-from django.utils.six import StringIO
 from django.utils.timezone import localtime, make_aware, now
 from django.utils.translation import ugettext_lazy as _
 

chrono/utils/requests_wrapper.py

@@ -16,13 +16,13 @@
 
 import hashlib
 import logging
+from io import BytesIO
 from urllib import parse
 
 from django.conf import settings
 from django.core.cache import cache
 from django.utils.encoding import smart_bytes
 from django.utils.http import urlencode
-from django.utils.six import BytesIO
 from requests import Response
 from requests import Session as RequestsSession
 from requests.auth import AuthBase