Update decorator to 5.0.6

[pyup-bot]

This PR updates decorator from 4.4.2 to 5.0.6.

Changelog

5.0.6

The decorator module was not copying the __module__ attribute anymore. Thanks to
Nikolay Markov for the notice.

5.0.5

Dropped support for Python < 3.5 with a substantial simplification of
the code base (now building a decorator does not require calling "exec").
Added a way to mimic functools.wraps-generated decorators.
Ported the Continuous Integration from Travis to GitHub.

Links

• PyPI: https://pypi.org/project/decorator
• Changelog: https://pyup.io/changelogs/decorator/
• Repo: https://github.com/micheles/decorator

[pyup-bot]

Closing this in favor of #52