Bump versions of Postorius to latest and fix urls.py

postorius/Dockerfile

@@ -15,8 +15,8 @@ RUN set -ex \
 	   	postgresql-dev mariadb-dev \
 	&& apk add --no-cache --virtual .mailman-rundeps bash \
 	   postgresql-client mysql-client py-mysqldb curl mailcap \
-	&& pip install -U Django>=1.11 pip \
-	&& pip install postorius==1.2.0a1 \
+	&& pip install -U Django==2.1.5 pip \
+	&& pip install postorius==1.2.3 \
 		uwsgi \
 		psycopg2 \
 		dj-database-url \

postorius/mailman-web/urls.py

@@ -30,5 +30,5 @@ urlpatterns = [
     url(r'', include('django_mailman3.urls')),
     url(r'^accounts/', include('allauth.urls')),
     # Django admin
-    url(r'^admin/', include(admin.site.urls)),
+    url(r'^admin/', admin.site.urls),
 ]