Update README.md

Author: froque

README.md

@@ -26,6 +26,8 @@ plugin works pretty much like the standard shell script support.
 
 ### [Unreleased]
 
+ - [Upgrade HtmlUnit from 2.x to 3.x](https://github.com/jenkinsci/powershell-plugin/pull/25)
+
 ### [Version 2.0] (2023-01-06)
 
  - [Use HTTPS instead of git](https://github.com/jenkinsci/powershell-plugin/pull/23)