Release v4.2.2

[puckowski]

What:

Update files for Release/v4.2.2.
Performed steps from comment on #4237:

• Create a branch from master release/v4.2.2
• Bump the Less version. (Unfortunately, this is still clunky, it's changed at package.json in root, and in /packages/less/ for historical reasons)
• Update the Changelog
• Run grunt dist - (Also clunky -- in a perfect world, we would not be committing dist files, but there are also tricky backwards compatibility problems which caused this initially.)
• Commit changed files to branch.
• Submit a PR to this repo.

Also tried to mirror #3814

I did not change the lock files. Those can be changed once the new version of Less.js is published to npm.

All merges have been bug fixes so I made the release a patch release.

Why:

Users can benefit from recent bug fixes.

Checklist:

• Documentation
• Added/updated unit tests
• Code complete

[puckowski]

Updated PR based on recent CI merges by @iChenLei (thank you!)

CI seems improved and not flaky.

I will investigate a more automated CHANGELOG solution in the future, my immediate priority was going through the backlog and fixing some bugs. So for this release I manually updated CHANGELOG.