Update changelog

Author: adamwathan

CHANGELOG.md

@@ -52,6 +52,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add `prefers-contrast` media query variants ([#8410](https://github.com/tailwindlabs/tailwindcss/pull/8410))
 - Add opacity support when referencing colors with `theme` function ([#8416](https://github.com/tailwindlabs/tailwindcss/pull/8416))
 - Add `postcss-import` support to the CLI ([#8437](https://github.com/tailwindlabs/tailwindcss/pull/8437))
+- Add `optional` variant ([#8486](https://github.com/tailwindlabs/tailwindcss/pull/8486))
 
 ## [3.0.24] - 2022-04-12