Add timestamp to the grouping key

The dimensionsKey contains all dimension fields value we want to use
to group the time series.

We need to add the timestamp to the key, so we only group together time
series with the same timestamp.

x-pack/metricbeat/module/gcp/metrics/timeseries.go

@@ -36,7 +36,8 @@ func createDimensionsKey(kv KeyValuePoint) string {
 	provider := getKeyValue(kv.ECS, "cloud.provider")
 	region := getKeyValue(kv.ECS, "cloud.region")
 
-	dimensionsKey := fmt.Sprintf("%s_%s_%s_%s_%s_%s",
+	dimensionsKey := fmt.Sprintf("%d_%s_%s_%s_%s_%s_%s",
+		kv.Timestamp.UnixNano(),
 		accountID,
 		az,
 		instanceID,