Update CHANGELOG.md

Move the change log line to unreleased section

Signed-off-by: Alvin Lin <[email protected]>

Author: alvinlin123

CHANGELOG.md

@@ -14,6 +14,7 @@
 * [CHANGE] Compactor block deletion mark migration, needed when upgrading from v1.7, is now disabled by default. #4597
 * [CHANGE] The `status_code` label on gRPC client metrics has changed from '200' and '500' to '2xx', '5xx', '4xx', 'cancel' or 'error'. 4601
 * [CHANGE] Memberlist: changed probe interval from `1s` to `5s` and probe timeout from `500ms` to `2s`. #4601
+* [FEATURE] Add shuffle sharding grouper and planner within compactor to allow further work towards parallelizing compaction #4357
 * [ENHANCEMENT] Update Go version to 1.17.5. #4602 #4604
 * [ENHANCEMENT] Keep track of discarded samples due to relabel configuration in `cortex_discarded_samples_total`. #4503
 * [ENHANCEMENT] Ruler: Add `-ruler.disable-rule-group-label` to disable the `rule_group` label on exported metrics. #4571