Update CHANGELOG.md

CHANGELOG.md

@@ -31,6 +31,7 @@
 
 * **Color picker**: Bug after using textbox input field to change/paste color string [#9769](https://github.com/grafana/grafana/issues/9769)
 * **Cloudwatch**: Fix for cloudwatch templating query `ec2_instance_attribute` [#9667](https://github.com/grafana/grafana/issues/9667), thanks [@mtanda](https://github.com/mtanda)
+* **Heatmap**: Fixed tooltip for "time series buckets" mode [#9332](https://github.com/grafana/grafana/issues/9332)
 
 # 4.6.1 (2017-11-01)