Bump django from 1.10.0 to 1.11.23 in /samples/django/django_user

Bumps [django](https://github.com/django/django) from 1.10.0 to 1.11.23.
- [Release notes](https://github.com/django/django/releases)
- [Commits](https://github.com/django/django/compare/1.10...1.11.23)

Signed-off-by: dependabot[bot] <support@github.com>
diff --git a/samples/django/django_user/requirements.txt b/samples/django/django_user/requirements.txt
index b42af1f..a3b3cfe 100644
--- a/samples/django/django_user/requirements.txt
+++ b/samples/django/django_user/requirements.txt
@@ -1,3 +1,3 @@
-Django==1.10.0
+Django==1.11.23
 oauth2client==3.0.0
 jsonpickle==0.9.3