Update django-slowtests to 1.1.1

[pyup-bot]

This PR updates django-slowtests from 0.5.1 to 1.1.1.

Changelog

1.1.1

- Return error code to shell in case of failed tests

1.1.0

- Added option to generate full tests reports by passing None to NUM_SLOW_TESTS

1.0.3

- Fixed cast error, leading to slow test ordering issues
- Fixed test case

1.0.2

- Handle django not installed case to ease installation

1.0.1

- Fixed report printed to console

1.0.0

-------
- Dropped Django 1.5* support
- Dropped Python 3.3* support
- Added Django 1.11.* support
- Fixed an issue preventing settings to be taken into account in some case (24)
- Added an option to generate a report on demand only using a command line
parameter
- Reports are now compatible with django tests' --parallel option
- Added an option to generate a json file containing the report, instead of
printing in to console.

Links

• PyPI: https://pypi.org/project/django-slowtests
• Changelog: https://pyup.io/changelogs/django-slowtests/
• Repo: https://github.com/realpython/django-slow-tests
• Docs: https://pythonhosted.org/django-slowtests/