DOC: update CHANGELOG

CHANGELOG.md

@@ -9,6 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added ###
 
+* Configuration options `REST_RESPONSE_LOG_FORMAT` and
+  `GRPC_RESPONSE_LOG_FORMAT` which control the format and information included
+  in the log message of any response of the respective API. See
+  `conf/core/server.conf` for more information.
+
 ### Changed ###
 
 ### Deprecated ###