update changelog

Signed-off-by: Albert <[email protected]>

Author: ac1214

CHANGELOG.md

@@ -47,6 +47,7 @@
 * [BUGFIX] Ingester: fixed ingester stuck on start up (LEAVING ring state) when `-ingester.heartbeat-period=0` and `-ingester.unregister-on-shutdown=false`. #4366
 * [BUGFIX] Querier: After query-frontend restart, querier may have lower than configured concurrency. #4417
 * [FEATURE] Add shuffle sharding grouper and planner within compactor to allow further work towards parallelizing compaction #4357
+* [ENHANCEMENT] Add a metric `cortex_compactor_remaining_planned_compactions` which will track the remaining planned compactions #4432
 
 ## 1.10.0 / 2021-08-03