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

)

Signed-off-by: dependabot[bot] <support@dependabot.com>

requirements.dev.txt

@@ -2,6 +2,6 @@ flake8==3.5.0
 Cython==0.29.3
 nose==1.3.7
 pycodestyle==2.3.1
-pylint==1.8.3
+pylint==1.9.4
 pytest==3.4.2
 pytest-watch==4.2.0