message: update changelog for v0.19.0
diff: @@ -6,7 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  -## [unreleased]
  +## [0.19.0]
  ### Changed
  - `emitDefinitions` now defaults to `false` (it previously defaulted to `true`)
  ### Fixed
  @@ -700,3 +700,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  [0.18.0]: https://github.com/rokucommunity/brighterscript/compare/v0.17.0...v0.18.0
  [0.18.1]: https://github.com/rokucommunity/brighterscript/compare/v0.18.0...v0.18.1
  [0.18.2]: https://github.com/rokucommunity/brighterscript/compare/v0.18.1...v0.18.2
  +[0.19.0]: https://github.com/rokucommunity/brighterscript/compare/v0.18.2...v0.19.0
  \ No newline at end of file
  