Fix docs

Author: yohfee

Diff for: docs/data-sources/aws_integration.md

@@ -39,4 +39,4 @@ data "mackerel_aws_integration" "foo" {
 * `enable` - Whether integration settings are enabled. Default is `true`.
 * `role` - The set of monitoring target’s service name or role name.
 * `excluded_metrics` - 	Metrics to exclude from integration.
-* `retire_automatically` - (EC2 only) Whether automatic retirement is enabled. 
+* `retire_automatically` - (EC2, RDS and ElastiCache only) Whether automatic retirement is enabled. 

Diff for: docs/resources/aws_integration.md

@@ -75,7 +75,7 @@ resource "mackerel_aws_integration" "baz" {
 * `enable` - Whether integration settings are enabled. Default is `true`.
 * `role` - The set of monitoring target’s service name or role name.
 * `excluded_metrics` - 	Metrics to exclude from integration.
-* `retire_automatically` - (EC2 only) Whether automatic retirement is enabled. 
+* `retire_automatically` - (EC2, RDS and ElastiCache only) Whether automatic retirement is enabled. 
 
 ## Attributes Reference