Log Message:
py-Willow: updated to 1.6.1

1.6.1 (2023-08-04)

Fix NUMBER_PATTERN regex for parsing SVG viewboxes (Joshua Munn)

1.6 (2023-07-13)

Configure linting with black, ruff and pre-commit. Add coverage reports (@zerolab)
Switch to flit for packaging, and PyPI trusted publishing (@zerolab)
Drop support for Python 3.7
Add AVIF support (Aman Pandey)
Add support for image optimization libraries via optimizer classes (@zerolab)
Add check for CMYK when saving as PNG (Stan Mattingly, @zerolab)