Make CI work for Windows on a push to the release branch

Add Changelog for v0.17.3, bump version number

update changelog for v0.18.0 (spack#30905)

update ffmpeg to avoid building for non-web environments

update ffmpeg package to auto-detect variants for emscripten

fix zlib and bzip2

fix npm docstring

Bump version number to v0.17.2

Fix execution of style tests

Update CHANGELOG.md for 0.17.0