Address RemovedInDjango40Warning

In Django 3.1, django.conf.urls.url() is deprecated
in favor of django.urls.re_path(). For more info see [1]
These were already replaced in Horizon repo by [2].

[1] https://docs.djangoproject.com/en/4.0/releases/3.1/#id2
[2] https://review.opendev.org/c/openstack/horizon/+/827093

Change-Id: I542d4a61168b294fda5a7f40b9759825cc4eef38

magnum_ui/content/cluster_templates/urls.py

@@ -12,7 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from django.conf.urls import url
+from django.urls import re_path
 from django.utils.translation import ugettext_lazy as _
 from horizon.browsers import views
 from magnum_ui.content.cluster_templates import panel
@@ -21,7 +21,8 @@ from magnum_ui.content.cluster_templates import panel
 title = _("Container Infra - Cluster Templates")
 page_title = panel.ClusterTemplates.name
 urlpatterns = [
-    url(r'^$',
-        views.AngularIndexView.as_view(title=title, page_title=page_title),
-        name='index'),
+    re_path(r'^$',
+            views.AngularIndexView.as_view(title=title,
+                                           page_title=page_title),
+            name='index'),
 ]

magnum_ui/content/clusters/urls.py

@@ -12,7 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from django.conf.urls import url
+from django.urls import re_path
 from django.utils.translation import ugettext_lazy as _
 from horizon.browsers import views
 from magnum_ui.content.clusters import panel
@@ -21,7 +21,7 @@ from magnum_ui.content.clusters import panel
 title = _("Container Infra - Clusters")
 page_title = panel.Clusters.name
 urlpatterns = [
-    url(r'^$',
-        views.AngularIndexView.as_view(title=title, page_title=page_title),
-        name='index'),
+    re_path(r'^$', views.AngularIndexView.as_view(
+            title=title, page_title=page_title),
+            name='index'),
 ]

magnum_ui/content/container_infra/quotas/urls.py

@@ -10,7 +10,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from django.conf.urls import url
+from django.urls import re_path
 from django.utils.translation import ugettext_lazy as _
 
 from horizon.browsers import views
@@ -20,7 +20,7 @@ from magnum_ui.content.container_infra.quotas import panel
 title = _("Container Infra - Quotas")
 page_title = panel.Quotas.name
 urlpatterns = [
-    url(r'^$',
-        views.AngularIndexView.as_view(title=title, page_title=page_title),
-        name='index'),
+    re_path(r'^$', views.AngularIndexView.as_view(
+            title=title, page_title=page_title),
+            name='index'),
 ]