Update changelog

Author: thecrypticace

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Support square bracket notation in paths ([#6519](https://github.com/tailwindlabs/tailwindcss/pull/6519))
 - Ensure all plugins are executed for a given candidate ([#6540](https://github.com/tailwindlabs/tailwindcss/pull/6540))
+- Don't mutate custom color palette when overriding per-plugin colors ([#6546](https://github.com/tailwindlabs/tailwindcss/pull/6546))
 
 ## [3.0.5] - 2021-12-15