chore: Update CHANGELOG

CHANGELOG.md

@@ -42,6 +42,7 @@
   * "Sharding Runtime State Sync" row - information about various state operations which occur when sharding is enabled (replication, fetch, marge, persist).
 * [ENHANCEMENT] Added 256MB memory ballast to querier. #369
 * [ENHANCEMENT] Update gsutil command for `not healthy index found` playbook #370
+* [ENHANCEMENT] Update `etcd-operator` to latest version (see https://github.com/grafana/jsonnet-libs/pull/480). #263
 * [BUGFIX] Fixed `CortexIngesterHasNotShippedBlocks` alert false positive in case an ingester instance had ingested samples in the past, then no traffic was received for a long period and then it started receiving samples again. #308
 * [BUGFIX] Alertmanager: fixed `--alertmanager.cluster.peers` CLI flag passed to alertmanager when HA is enabled. #329
 * [BUGFIX] Fixed `CortexInconsistentRuntimeConfig` metric. #335