Update python-qscintilla to 2.11.6 and drop python2 support

Summary:
Full changelog here

All existing packages in the repository doesn't require python2 support for python-qscintilla.

This version fixes the issue of tortoisehg which crashes when opening console.

Depends on D10090

Signed-off-by: Algent Albrahimi <algent@protonmail.com>

Test Plan:

• Run tortoisehg and submit a commit. Open and close console.
• Install and run autokey-py3-qt and qgis.

Reviewers: Triage Team, DataDrake

Reviewed By: Triage Team, DataDrake

Subscribers: DataDrake

Differential Revision: https://dev.getsol.us/D10091