Update changelog

Author: Seldaek

CHANGELOG.md

@@ -3,6 +3,11 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+### [1.5.0] 2019-03-19
+
+  * Added: some support for date versions (e.g. 201903) in `~` operator
+  * Fixed: support for stabilities in `~` operator was inconsistent
+
 ### [1.4.2] 2016-08-30
 
   * Fixed: collapsing of complex constraints lead to buggy constraints