Fix tests, fix Django deprecation warnings

MANIFEST.in

@@ -1,4 +1,2 @@
 include COPYING
 include README.rst
-include requirements.txt
-include requirements/*.txt

gvacommon/tests/test_viewmixins.py

@@ -32,6 +32,7 @@ from django.views.generic import View
 if not settings.configured:
     settings.configure(
         DEBUG=True,
+        SECRET_KEY="unused#secret",
         ROOT_URLCONF='tests',
         TEMPLATE_DIRS=['.'],
         DATABASES={

gvacommon/viewmixins.py

@@ -1,6 +1,6 @@
 #
 # gvacommon - common parts of gnuviechadmin
-# Copyright (C) 2015-2016  Jan Dittberner
+# Copyright (C) 2015-2023  Jan Dittberner
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License as published by
@@ -19,11 +19,9 @@
 This module defines mixins for gnuviechadmin views.
 
 """
-from __future__ import unicode_literals
-
 from django.contrib.auth.mixins import LoginRequiredMixin
 from django.http import HttpResponseForbidden
-from django.utils.translation import ugettext as _
+from django.utils.translation import gettext as _
 
 
 class StaffOrSelfLoginRequiredMixin(LoginRequiredMixin):