Update changelog.md

changelog.md

@@ -2,8 +2,11 @@
 
 All notable changes to this project will be documented in this file.
 
+## [0.21] - 2021-09-14
+- Delete left-over and unmanaged folders
+
 ## [0.20] - 2021-09-13
-- Don't automatically create ignored folders, just ignore them if they are present.
+- Don't automatically create ignored folders, just ignore them if they are present
 
 ## [0.19] - 2021-09-13
 - [POL1-501] create config option ignored_folders for provisioning folders with manually maintained dashboards