cloud: add release notes 2024-10-29 (#19220)

tidb-cloud/tidb-cloud-release-notes.md

@@ -8,6 +8,14 @@ aliases: ['/tidbcloud/supported-tidb-versions','/tidbcloud/release-notes']
 
 This page lists the release notes of [TiDB Cloud](https://www.pingcap.com/tidb-cloud/) in 2024.
 
+## October 29, 2024
+
+**General changes**
+
+- New metric: add `tidbcloud_changefeed_checkpoint_ts` for Prometheus integration.
+
+    This metric tracks the checkpoint timestamp of a changefeed, representing the largest TSO (Timestamp Oracle) successfully written to the downstream. For more information on available metrics, see [Integrate TiDB Cloud with Prometheus and Grafana (Beta)](/tidb-cloud/monitor-prometheus-and-grafana-integration.md#metrics-available-to-prometheus).
+
 ## October 22, 2024
 
 **General changes**