update changelog

Author: RobinMalfait

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Make sure `contain-*` utility variables resolve to a valid value ([#13521](https://github.com/tailwindlabs/tailwindcss/pull/13521))
 
+### Changed
+
+- Remove automatic `var(…)` injection ([#13537](https://github.com/tailwindlabs/tailwindcss/pull/13537))
+
 ## Changed
 
 - Use `rem` units for breakpoints by default instead of `px` ([#13469](https://github.com/tailwindlabs/tailwindcss/pull/13469))
@@ -163,3 +167,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Move the CLI into a separate `@tailwindcss/cli` package ([#13095](https://github.com/tailwindlabs/tailwindcss/pull/13095))
 
 ## [4.0.0-alpha.1] - 2024-03-06
+