Add change log entry.

Signed-off-by: Carmen Bianca BAKKER <[email protected]>

CHANGELOG.md

@@ -49,7 +49,9 @@ CLI command and its behaviour. There are no guarantees of stability for the
 
 ### Changed
 
-- Alpine Docker image now uses 3.18 as base. (#846)
+- No longer create separate Alpine, Alpine-extra and Debian Docker images. All
+  future images are now debian:slim images. The Debian image used to be based on
+  the python:slim image, which used Debian under the hood. (#849)
 
 ### Deprecated