Update changelog

Author: thecrypticace

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Fix preflight border color fallback ([#7288](https://github.com/tailwindlabs/tailwindcss/pull/7288))
+- Correctly parse shadow lengths without a leading zero ([#7289](https://github.com/tailwindlabs/tailwindcss/pull/7289))
 
 ## [3.0.18] - 2022-01-28