v1.6 AVIF and support for optimizer libraries

🖼️ This release adds support for AVIF images via pillow-heif for Pillow, or ImageMagick 7.0.25+ for Wand.

🚀 It also introduces a new optimizer mechanism that allows optimizing images using dedicated libraries. Out of the box, Willow comes with optimizers for gifsicle, jpegoptim, optipng, pngquant and cwebp.

🐍 Willow no longer supports Python 3.7.

What's Changed

• Add linting by @zerolab in #116
• Switch to using flit for packaging by @zerolab in #117
• Use RTD config v2, update Sphinx configuration and use the Wagtail sphinx theme by @zerolab in #118
• Fix minor typos in README by @lb- in #120
• Re-add williow.image import in init by @zerolab in #121
• Add code coverage by @zerolab in #122
• Add check for CMYK when saving as PNG by @zerolab in #123
• Add AVIF support by @salty-ivy in #115
• Image optimisation operations by @zerolab in #69
• Add optional heif dependency to allow installing via pip install willow[heif] by @zerolab in #126

New Contributors

• @lb- made their first contribution in #120
• @salty-ivy made their first contribution in #115

Full Changelog: v1.5...v1.6