Updated CHANGELOG.md

Author: colega

CHANGELOG.md

@@ -23,11 +23,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Security
 - Nothing
 
+## [1.4.0] - 2019-05-30
+### Changed
+- Baggage key is now a public string `"logctx-data-map-string-interface"` that can be set and read by anyone from any package.
+The type of that baggage will be always `map[string]interface{}`
+
+### Added
+- `BaggageContextKey` constant that defines that string
+- `Baggage(ctx) map[string]interface{}` that allows reading the underlying baggage. 
+
 ## [1.3.0] - 2019-03-18
 ### Added
 - `Level` now implements the `envconfig.Decoder` interface so it can be used in config types
 
-
 ## [1.2.0] - 2019-02-27
 ### Added
 - `ConfigureDefaultLogger` boilerplate for logger configuration