Update pyflakes to 2.0.0

[pyup-bot]

This PR updates pyflakes from 1.6.0 to 2.0.0.

Changelog

### 2.0.0 ``` - Drop support for EOL Python <2.7 and 3.2-3.3 - Check for unused exception binding in `except:` block - Handle string literal type annotations - Ignore redefinitions of `_`, unless originally defined by import - Support `__class__` without `self` in Python 3 - Issue an error for `raise NotImplemented(...)` ```

Links

- PyPI: https://pypi.org/project/pyflakes - Changelog: https://pyup.io/changelogs/pyflakes/ - Repo: https://github.com/PyCQA/pyflakes

[coveralls]

Pull Request Test Coverage Report for Build 486

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage remained the same at 97.767%

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Files with Coverage Reduction	New Missed Lines	%
astrality/filewatcher.py	4	97.06%
<!--	Total:	4		-->

Totals
Change from base Build 482:	0.0%
Covered Lines:	4334
Relevant Lines:	4433

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💛 - Coveralls