added info for v0.12.4

Author: Greg S

CHANGELOG.md

@@ -3,6 +3,14 @@ All notable changes to this project will be documented in this file.
 
 The changelog format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
+## [0.12.4] - 03-Jul-2019
+
+**Milestone**: Dragon
+
+- Added export for Sha3Hasher
+- Added export for nacl_catapult
+- Added changelog milestone attribution
+
 ## [0.12.3] - 20-Jun-2019
 
 **Milestone**: Dragon
@@ -136,6 +144,7 @@ The changelog format is based on [Keep a Changelog](https://keepachangelog.com/e
 
 - Initial code release.
 
+[0.12.4]: https://github.com/nemtech/nem2-sdk-typescript-javascript/compare/v0.12.3...v0.12.4
 [0.12.3]: https://github.com/nemtech/nem2-sdk-typescript-javascript/compare/v0.12.2...v0.12.3
 [0.12.2]: https://github.com/nemtech/nem2-sdk-typescript-javascript/compare/v0.12.1...v0.12.2
 [0.12.1]: https://github.com/nemtech/nem2-sdk-typescript-javascript/compare/v0.12.0...v0.12.1

README.md

@@ -12,9 +12,9 @@ with the NEM2 (a.k.a Catapult)
 
 ### _Dragon_ Network Compatibility ([email protected])
 
-Due to a network upgrade with [catapult-server@dragon](https://github.com/nemtech/catapult-server/releases/tag/v0.4.0.1) version, **it is recommended to use this package's 0.12.3 version and upwards to use this package with Dragon versioned networks**.
+Due to a network upgrade with [catapult-server@dragon](https://github.com/nemtech/catapult-server/releases/tag/v0.4.0.1) version, **it is recommended to use this package's 0.12.4 version and upwards to use this package with Dragon versioned networks**.
 
-The upgrade to this package's [version v0.12.3](https://github.com/nemtech/nem2-sdk-typescript-javascript/releases/tag/v0.12.3) is mandatory for **dragon compatibility**.
+The upgrade to this package's [version v0.12.4](https://github.com/nemtech/nem2-sdk-typescript-javascript/releases/tag/v0.12.4) is mandatory for **dragon compatibility**.
 
 ### _Cow_ Network Compatibility ([email protected])