Update CHANGELOG.md

Author: tjcelaya

CHANGELOG.md

@@ -2,6 +2,11 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [4.0.6] - ?
+
+### Fixed
+ - [Removed reflective mofification of PKCS#11 Security Provider's algorithms map](https://github.com/joyent/java-http-signature/issues/45) which was incorrectly serializing ECDSA keys.
+
 ## [4.0.5] - 2017-10-20
 
 ### Fixed