Updated changelog

Signed-off-by: Ram Cohen <[email protected]>

CHANGELOG.md

@@ -48,6 +48,7 @@ To learn more about our roadmap, we recommend reading [this document](ROADMAP.md
 - **General:** Use `mili` scale for the returned metrics ([#3135](https://github.com/kedacore/keda/issue/3135))
 - **General:** Use more readable timestamps in KEDA Operator logs ([#3066](https://github.com/kedacore/keda/issue/3066))
 - **AWS SQS Queue Scaler:** Support for scaling to include in-flight messages. ([#3133](https://github.com/kedacore/keda/issues/3133))
+- **GCP Stackdriver Scaler:** Added aggregation parameters ([#3008](https://github.com/kedacore/keda/issues/3008))
 - **Prometheus Scaler:** Add ignoreNullValues to return error when prometheus return null in values ([#3065](https://github.com/kedacore/keda/issues/3065))
 - **Selenium Grid Scaler:** Edge active sessions not being properly counted ([#2709](https://github.com/kedacore/keda/issues/2709))
 - **Selenium Grid Scaler:** Max Sessions implementation issue ([#3061](https://github.com/kedacore/keda/issues/3061))