update changelog for 6.6.6 release
@@ -6,7 +6,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
and this project adheres to [Semantic
Versioning](http://semver.org/spec/v2.0.0.html).
-## [6.6.6] - ???
+## [6.6.6] - 2022-02-16
### Fixed
