Prep changelog for next release (#59)

Author: JordanMartinez

CHANGELOG.md

@@ -4,6 +4,17 @@ Notable changes to this project are documented in this file. The format is based
 
 ## [Unreleased]
 
+Breaking changes:
+
+New features:
+
+Bugfixes:
+
+Other improvements:
+
+
+## [v9.0.0](https://github.com/purescript-node/purescript-node-buffer/releases/tag/v9.0.0) - 2022-06-05
+
 Breaking changes:
 - Expose Buffer API using typeclass-less API witout removing typeclass API (#53 by @JordanMartinez)