Update changelog for 1.4.0

Author: turtle0x1

CHANGELOG.md

@@ -4,10 +4,14 @@ All Notable changes to `php-lxd` will be documented in this file.
 
 Updates should follow the [Keep a CHANGELOG](http://keepachangelog.com/) principles.
 
+# [1.4.0]
+## Added
+  IncusOS kernel GET api
+
 # [1.3.0]
 ## Added
   Support for some IncusOS GET/POST API's
-  
+
 # [1.2.0]
 ## Fixed
     Derpciation warnings caused by PHP 8.4