Update forms.py

Updates ugettext to gettext as per latest dependency.

radio/forms.py

@@ -1,7 +1,7 @@
 import re
 from django import forms
 from django.contrib.auth.models import User
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 
 from django_select2.forms import (
  HeavySelect2MultipleWidget, HeavySelect2Widget, ModelSelect2MultipleWidget,