message: Add changelog entry for minimum Rust version bump
diff: @@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  ## 0.5.0-dev
  +### Packaging
  +
  +- Minimum Rust version has been bumped to 1.39.0
  +
  ### Added
  - Default Command+N keybinding for SpawnNewInstance on macOS
  