message: add date in changelog for v0.12.2
diff: @@ -6,7 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  -## [0.12.2]
  +## [0.12.2] - 2020-07=16
  ### Added
  - Expose `ProgramBuilder.transpile()` method to make it easier for tools to transpile programmatically. [#154](https://github.com/rokucommunity/brighterscript/issues/154)
  ### Fixed
  