Update CHANGELOG.md

Author: garyb

CHANGELOG.md

@@ -7,12 +7,17 @@ Notable changes to this project are documented in this file. The format is based
 Breaking changes:
 
 New features:
-- MonadST instance for Aff
 
 Bugfixes:
 
 Other improvements:
 
+
+## [v7.1.0](https://github.com/purescript-contrib/purescript-aff/releases/tag/v7.1.0) - 2022-08-06
+
+New features:
+- MonadST instance for Aff (#213 by @Mateiadrielrafael)
+
 ## [v7.0.0](https://github.com/purescript-contrib/purescript-aff/releases/tag/v7.0.0) - 2022-04-27
 
 Breaking changes: