v1.577.0

• Consolidate clean-theme class naming and organization
  #2671

v1.576.0

• Fail more gracefully in unsupported versions of Edge Legacy
  #2685

v1.575.0

Bump commander from 6.1.0 to 6.2.0

Bumps [commander](https://github.com/tj/commander.js) from 6.1.0 to 6.2.0.
- [Release notes](https://github.com/tj/commander.js/releases)
- [Changelog](https://github.com/tj/commander.js/blob/master/CHANGELOG.md)
- [Commits](https://github.com/tj/commander.js/compare/v6.1.0...v6.2.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

v1.574.0

• Attempt to fix prod deploy failure after concurrent builds
  #2669

v1.573.0

• Remove polyfills for features supported by all target browsers
  #2668

v1.572.0

• Run "yarn upgrade" #2666

v1.571.0

• Enable terser workarounds for Safari 10
  #2665

v1.570.0

• Remove unused iframe attributes #2663

v1.569.0

• Merge Host and Sidebar classes #2662

v1.568.0

• Rewrite bucket-generating logic #2647