graphics/py-pillow: Update to 6.2.0

Release Notes:

• https://pillow.readthedocs.io/en/latest/releasenotes/index.html

Detailed Changelog:

• https://github.com/python-pillow/Pillow/blob/6.2.0/CHANGES.rst

PR: 241268
Approved by: koobs (maintainer)
MFH: 2019Q4
Security: 998ca824-ef55-11e9-b81f-3085a9a95629