Update to Django 1.11.23

[simpsonw]

Description

Upgrade to Django 1.11.23.

Checklist before merging Pull Requests

• New test(s) included to reproduce the bug/verify the feature
• Add an entry in the changelog
• Documentation created/updated (include links)
• If creating/modifying DB models which will contain secrets or sensitive information, PR to clank updating sanitation queries in roles/sanitary-sql-access/templates/sanitize-dump.sh.j2
• Reviewed and approved by at least one other contributor.
• New variables supported in Clank

[calvinmclean]

We just need a changelog entry and then it is good-to-go

[simpsonw]

@calvinmclean Changelog updated!

[coveralls]

Coverage remained the same at 39.284% when pulling 8b066fd on simpsonw:django_update into 52beb90 on cyverse:master.