Update CHANGELOG.md

Author: thomashoneyman

CHANGELOG.md

@@ -10,6 +10,10 @@ New features:
 
 Bugfixes:
 
+Other improvements:
+
+## [v4.0.1](https://github.com/purescript/purescript-minibench/releases/tag/v4.0.1) - 2022-09-23
+
 Other improvements:
 - Update FFI to use a more direct and portable convention (#25 by @natefaubion)