Update pylint to 2.4.1

[pyup-bot]

This PR updates pylint from 2.4.0 to 2.4.1.

Changelog

2.4.1

===========================

Release date: 2019-09-25


* Exempt type checking definitions defined in both clauses of a type checking guard

Close 3127


* Exempt type checking definitions inside the type check guard

In a7f236528bb3758886b97285a56f3f9ce5b13a99 we added basic support
for emitting `used-before-assignment` if a variable was only defined
inside a type checking guard (using `TYPE_CHECKING` variable from `typing`)
Unfortunately that missed the case of using those type checking imports
inside the guard itself, which triggered spurious used-before-assignment errors.

Close 3119

* Require astroid >= 2.3 to avoid any compatibility issues.

Links

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