Merge pull request #283 from Art4/release-1-8-1

Release v1.8.1

Author: Art4

CHANGELOG.md

@@ -5,7 +5,9 @@ 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](https://github.com/kbsali/php-redmine-api/compare/v1.8.0...master)
+## [Unreleased](https://github.com/kbsali/php-redmine-api/compare/v1.8.1...v1.x)
+
+## [v1.8.1](https://github.com/kbsali/php-redmine-api/compare/v1.8.0...v1.8.1) - 2021-06-01
 
 ### Fixed