Add changelog entry.

CHANGELOG.md

@@ -103,6 +103,7 @@
 * [BUGFIX] Querier: fix issue where queries fail with "context canceled" error when an ingester or store-gateway fails healthcheck while the query is in progress. #6550
 * [BUGFIX] Tracing: When creating an OpenTelemetry tracing span, add it to the context for later retrieval. #6614
 * [BUGFIX] Querier: always report query results to query-frontends, even when cancelled, to ensure query-frontends don't wait for results that will otherwise never arrive. #6703
+* [BUGFIX] Querier: attempt to query ingesters in PENDING state, to reduce the likelihood that scaling up the number of ingesters in multiple zones simultaneously causes a read outage. #6726
 
 ### Mixin