Add support for Oracle multitenant container database engines (#167)

Author: wata727

rules/aws_db_instance_invalid_engine.go

@@ -28,7 +28,9 @@ func NewAwsDBInstanceInvalidEngineRule() *AwsDBInstanceInvalidEngineRule {
 			"mariadb":           true,
 			"mysql":             true,
 			"oracle-ee":         true,
+			"oracle-ee-cdb":     true,
 			"oracle-se2":        true,
+			"oracle-se2-cdb":    true,
 			"oracle-se1":        true,
 			"oracle-se":         true,
 			"postgres":          true,