[BUG] The policy FG_R00093 doesn't handle the Serverless RDS Cluster properly

[rsareth]

Describe the bug
The policy FG_R00093 doesn't handled properly the serverless RDS Cluster. In the code, I don't see anything telling that if the rds cluster has the engine serverless, it shouldn't raise an alert.

It is based on this documentation: https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/rds_cluster#storage_encrypted

How you're running Regula

• I'm using Regula v2.9.1

Operating System
Mac OS and Linux

Steps to reproduce

• Step 1 - Create this TF file with this content:

resource "aws_rds_cluster" "serverless_cluster" {
  engine_mode             = "serverless"
}

• Step 2 - Run regula:

$ regula run .

FG_R00093: RDS instances should be encrypted [High]
           https://docs.fugue.co/FG_R00093.html

  [1]: aws_rds_cluster.serverless_cluster
       in rds.tf:1:1
[...]

Thank you by advance to look at that.

Rasmey