message: Update CHANGELOG.md 0.21.0
diff: # Changelog
  +## 0.21.0
  +
  +- Imports/exports that are ambient (declarations, types, interfaces, etc) or are not used in value positions no longer generate `require` statements.
  +- For ... of loops are now translated using `ipairs`.
  +- Added support for `array.reduce`.
  +- Added support for `import foo = bar.baz;` statements.
  +
  +- Fixed some issues with binding pattern parameter default values.
  +- Fixed some issues with variable naming.
  +- Enabled prettier on the entire codebase.
  +
  ## 0.20.0
  - Added support for `string.repeat`, `string.padStart` and `string.padEnd`.
  