update cloudwatch docs

docs/sources/datasources/cloudwatch.md

@@ -63,15 +63,10 @@ Name | Description
 `namespaces()` | Returns a list of namespaces CloudWatch support.
 `metrics(namespace)` | Returns a list of metrics in the namespace.
 `dimension_keys(namespace)` | Returns a list of dimension keys in the namespace.
-`dimension_values(region, namespace, metric)` | Returns a list of dimension values matching the specified `region`, `namespace` and `metric`.
+`dimension_values(region, namespace, metric, dimension_key)` | Returns a list of dimension values matching the specified `region`, `namespace`, `metric` and `dimension_key`.
 
 For details about the metrics CloudWatch provides, please refer to the [CloudWatch documentation](https://docs.aws.amazon.com/AmazonCloudWatch/latest/DeveloperGuide/CW_Support_For_AWS.html).
 
-If you want to filter dimension values by other dimension key/value pair, you can specify optional parameter like this.
-```sql
-dimension_values(region, namespace, metric, dim_key1=dim_val1,dim_key2=dim_val2,...)
-```
-
 ![](/img/v2/cloudwatch_templating.png)
 
 ## Cost