Update CHANGELOG.md

Update the changelog.

Author: lukecav

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/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [Version 1.1.21] - 2023-07-18
+
+* Bump WooCommerce tested version.
+
 ## [Version 1.1.20] - 2023-06-13
 
 * Bump WooCommerce tested version.
@@ -160,3 +164,4 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 [Version 1.1.18]: https://github.com/lukecav/performance-improvements-for-woocommerce/releases/tag/v1.1.18
 [Version 1.1.19]: https://github.com/lukecav/performance-improvements-for-woocommerce/releases/tag/v1.1.19
 [Version 1.1.20]: https://github.com/lukecav/performance-improvements-for-woocommerce/releases/tag/v1.1.20
+[Version 1.1.21]: https://github.com/lukecav/performance-improvements-for-woocommerce/releases/tag/v1.1.21