Add ChangeLog entry for v0.2.0.

Author: micaeljtoliveira

ChangeLog.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
+## [0.2.0] - 2023-08-29
+
+### Changed
+
+- Components and build system to match CESM [064022e](https://github.com/ESCOMP/CESM/commit/064022ed14bcc48dbb632dabc36a741ae0859822).
+
 ## [0.1.0] - 2023-08-16
 
 ### Added