UPDATED changelog

Author: infobip-ci

CHANGELOG.md

@@ -4,6 +4,19 @@ All notable changes to the library will be documented in this file.
 
 The format of the file is based on [Keep a Changelog](http://keepachangelog.com/) and this library adheres to [Semantic Versioning](http://semver.org/) as mentioned in the [README.md][readme] file.
 
+## [ [5.1.0](https://github.com/infobip/infobip-api-php-client/releases/tag/5.1.0) ] - 2023-04-24
+
+⚠️ **IMPORTANT NOTE:** Obsolete models that are not used since release 5.0.0 have been removed. You should not use them anymore.
+
+### Removed
+- Obsolete code pre 5.0.0 release (API classes, models)
+
+### Fixed
+- Email sending with attachments and inline images
+
+### Changed
+- Updated email README
+
 ## [ [5.0.0](https://github.com/infobip/infobip-api-php-client/releases/tag/5.0.0) ] - 2023-03-01
 
 ⚠️ **IMPORTANT NOTE:** This release contains breaking changes!