[PyUP] Update django-appconf to 1.0.3

[pyup-bot]

This PR updates django-appconf from 1.0.2 to 1.0.3.

Changelog

1.0.3

-----------------

Packaging metadata updates:

* Update tox configuration to match Django Python support map

* Drop support for Django 1.8, 1.9 and 1.10
* Drop support for python 3.3

* Confirm support for Django 1.11, 2.0 and 2.1
* Confirm support for python 3.7

Links

• PyPI: https://pypi.org/project/django-appconf
• Changelog: https://pyup.io/changelogs/django-appconf/
• Docs: https://django-appconf.readthedocs.io/

[pyup-bot]

Closing this in favor of #297