Update changelog

Author: adamwathan

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - New `preserveHtmlElements` option for `purge` ([#2283](https://github.com/tailwindlabs/tailwindcss/pull/2283))
 - New `layers` mode for `purge` ([#2288](https://github.com/tailwindlabs/tailwindcss/pull/2288))
 - New `font-variant-numeric` utilities ([#2305](https://github.com/tailwindlabs/tailwindcss/pull/2305))
+- Support configuring variants as functions ([#2309](https://github.com/tailwindlabs/tailwindcss/pull/2309))
 
 ### Deprecated