Update pylint to 2.7.4

[cdce8p]

Proposed change

Changelog: http://pylint.pycqa.org/en/latest/whatsnew/changelog.html#what-s-new-in-pylint-2-7-4
Full diff: pylint-dev/pylint@pylint-2.7.3...pylint-2.7.4

Fixes two regession issues with 2.7.3

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests