udpate changelog

Author: spipu

CHANGELOG.md

@@ -4,6 +4,7 @@ All notable changes to this project will be documented in this file.
 
 ## [5.3.2](https://github.com/spipu/html2pdf/compare/v5.3.1...master) - 2025-xx-xx
 
+  * add readonly attribute support for input and textarea - thanks to @kkevinchoo
   * improve Security service to be able to allow specific hosts
   * update doc about Security service
   * fix security issue on css background-image validation - thanks to Aleksey Solovev and Nikita Sveshnikov ([Positive Technologies](https://www.ptsecurity.com))