Make ready for 3.3.1-rc.1
diff --git a/CHANGELOG.md b/CHANGELOG.md
index feba83d..2af59bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,7 @@
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/) and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [3.3.1-rc.1] - 2024-06-20
 
 ### Added