Update Changelog.

Author: stevesg

CHANGELOG.md

@@ -32,6 +32,11 @@
 * [ENHANCEMENT] Ruler dashboard: added "Per route p99 latency" panel in the "Configuration API" row. #353
 * [ENHANCEMENT] Increased the `for` duration of the `CortexIngesterReachingSeriesLimit` warning alert to 3h. #362
 * [ENHANCEMENT] Added a new tier (`medium_small_user`) so we have another tier between 100K and 1Mil active series. #364
+* [ENHANCEMENT] Extend Alertmanager dashboard: #313
+  * "Tenants" stat panel - shows number of discovered tenant configurations.
+  * "Tenant Configuration Sync" row - information about the configuration sync procedure.
+  * "Sharding Initial State Sync" row - information about the initial state sync procedure when sharding is enabled.
+  * "Sharding State Operations" row - information about various state operations which occur when sharding is enabled (replication, fetch, marge, persist).
 * [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