updated changelog

Signed-off-by: Christoph Massmann <[email protected]>

Author: ma4nn

CHANGELOG.md

@@ -4,9 +4,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [3.0.0] - 2021-06-01
+### Changed
+- Refactored logic for pdf attachment files
+- Switched from deprecated FPDF library to TCPDF
+
 ## [2.2.0] - 2021-02-05
 ### Added
 - Added support for PHP 8
+### Changed
 - Updated PDF libraries
 
 ## [2.1.0] - 2020-12-19