DOC: update CHANGELOG

CHANGELOG.md

@@ -13,9 +13,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   by setting the server property `EXT_ENTITY_STATE=ENABLED`. See
   [!62](https://gitlab.com/caosdb/caosdb-server/-/merge_requests/62) for more
   information.
-* `ETag` property for the query. The `ETag` tags a server state and is being
-  updated each time the server state is being updated (i.e. the stored entities
-  change). This can be used to debug the query cache and also allows a client
 * `ETag` property for the query. The `ETag` is assigned to the query cache
   each time the cache is cleared (currently whenever the server state is being
   updated, i.e. the stored entities change).