message: CHORE: update changelog for 0.2.3 release
diff: +## X.Y.Z (INSERT_DATE_HERE)
  +
  +#### Major Changes
  +- [Custom Token Patterns to Support Lexer Context.](https://github.com/SAP/chevrotain/issues/360)
  +
  +#### Documentation
  +- [Example of lexing python style indentation.](https://github.com/SAP/chevrotain/issues/352)
  +
  +
  +
  ## 0.22.0 (1-27-2017)
  #### Minor Changes
  