Bump pylint from 1.8.3 to 1.9.4 (#52)

Bumps [pylint](https://github.com/PyCQA/pylint) from 1.8.3 to 1.9.4.
- [Release notes](https://github.com/PyCQA/pylint/releases)
- [Changelog](https://github.com/PyCQA/pylint/blob/pylint-1.9.4/ChangeLog)
- [Commits](https://github.com/PyCQA/pylint/compare/pylint-1.8.3...pylint-1.9.4

)

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