Changelog updated for version 0.7.3

Author: remorhaz

CHANGELOG.md

@@ -4,7 +4,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [0.7.3] - 2020-03-12
 ### Added
 - Upgraded `remorhaz/php-unilex` to version 0.3.1.
 - Names in dot-notation now allow non-ASCII characters.