Update python-astroid to 1.6.1

Summary:

• Fix a crash when __annotations__ access a parent's __init__ that does not have arguments.

Source

Test Plan: Tested with pylint.

Reviewers: Triage Team, JoshStrobl

Reviewed By: Triage Team, JoshStrobl

Subscribers: JoshStrobl

Differential Revision: https://dev.solus-project.com/D2071