Update CHANGELOG.md

Author: adamwathan

CHANGELOG.md

@@ -30,6 +30,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Switch to positional argument + object for modifiers ([#9541](https://github.com/tailwindlabs/tailwindcss/pull/9541))
 - Add new `min` and `max` variants ([#9558](https://github.com/tailwindlabs/tailwindcss/pull/9558))
 - Add aria variants ([#9557](https://github.com/tailwindlabs/tailwindcss/pull/9557))
+- Upgrade to `postcss-nested` v6.0 ([#9546](https://github.com/tailwindlabs/tailwindcss/pull/9546))
 
 ### Fixed