Release 4.2.0

[benoit74]

• Secure the CI is green on git main
• Update the Changelog
• Update version in package.json
• Update package-lock.json by running npm i
• Create a tag on git
• Make new release on Github
• Secure new version is published on https://www.npmjs.com/package/@openzim/libzim
• Create issues to request dependency upgrade in MWoffliner and Phet scrapers
• Close current milestone and create new one incrementaly (a priori a minor version)
• Create new empty entry in Changelog (placeholder for future entries)
• Update version to next patch + dev0: x.y.z+1-dev0
• Advertise this new version
• Create new issue in next milestone with this checklist