Fix win32 build

Merge branch 'main' of https://github.com/imazen/imageflow

Update SECURITY.md

rustup update on macos

Update base_dockerfiles.yml

Fixes #615 - Bug in zoom calculation

Fix #613, 24-bit PNG files with a zero alpha channel are now properly…

… encoded when using lossy PNG and when no transparency-inducing operations are performed.

Make MutProtect actually clone nodes for each branch, then use MutPro…

…tect on White Balance and Round Corners

Exclude catch.hpp from spellcheck

Add support for buildTransitive in NuGet packages