adding to change log

Author: ddey2

CHANGELOG.md

@@ -5,6 +5,10 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## Unreleased
+
+## Fixed
+- Disabled button while create dataset ajax call is still going on [#311](https://github.com/clowder-framework/clowder/issues/311)
 
 ## 1.21.0 - 2022-08-23