Correct error caused by django version upgrade in Municípios

Signed-off-by: Luciano Almeida <lucianoalmeida@interlegis.leg.br>

sigi/apps/utils/__init__.py

@@ -3,6 +3,7 @@ from unicodedata import normalize
 
 from django.contrib import admin
 from django.db import models
+from django.contrib.admin import ModelAdmin
 
 
 class SearchField(models.TextField):
@@ -39,4 +40,4 @@ def queryset_ascii(self, request):
     if 'q' in request.GET:
         request.GET._mutable = True
         request.GET['q'] = to_ascii(request.GET['q'])
-    return admin.ModelAdmin.queryset(self, request)
+    return admin.ModelAdmin.get_queryset(self, request)