1.21.0

This version is a fork by @vain0x.

Below is copied from CHANGELOG:

• Add definition provider for javascript files
• Refresh internal cache on save css files
• Merged PRs:
  • Use activationevents to prevent launching the ext on unrelated workspaces by jens1o · Pull Request #124
  • Allow escaped characters in css selectors by canvasplay · Pull Request #289
  • Add curly bracket to JS provider for use in React. by bilherron · Pull Request #371
• Update packages