import url functions from django.urls (#50110)

passerelle_reunion_fsn/models.py

@@ -27,7 +27,7 @@ import tempfile
 from django.conf import settings
 from django.contrib.postgres.fields import JSONField
 from django.core.files import File
-from django.core.urlresolvers import reverse
+from django.urls import reverse
 from django.db import models, transaction
 from django.http import FileResponse, HttpResponse
 from django.utils import dateformat, six