update changelog

Author: RobinMalfait

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Allow spaces spaces around operators in attribute selector variants ([#14703](https://github.com/tailwindlabs/tailwindcss/pull/14703))
 - _Upgrade (experimental)_: Migrate `flex-grow` to `grow` and `flex-shrink` to `shrink` ([#14721](https://github.com/tailwindlabs/tailwindcss/pull/14721))
 - _Upgrade (experimental)_: Minify arbitrary values when printing candidates ([#14720](https://github.com/tailwindlabs/tailwindcss/pull/14720))
+- _Upgrade (experimental)_: Ensure we migrate `theme(spacing.1)` to `var(--spacing-1)` correctly ([#14724](https://github.com/tailwindlabs/tailwindcss/pull/14724))
 
 ### Changed