Update changelog

Author: adamwathan

CHANGELOG.md

@@ -7,7 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-- Nothing yet!
+### Added
+
+- Support opacity values in increments of `0.25` by default ([#14980](https://github.com/tailwindlabs/tailwindcss/pull/14980))
 
 ## [4.0.0-alpha.33] - 2024-11-11