Ensure default ports are not used by Amazon Relational Database Service (Amazon RDS) instances

AWS RDS database instances are using the default ports which may expose them to brute-force and dictionary attacks.

In AWS Console -

1. Sign in to the AWS Console and open the RDS Console.
2. Under Databases, choose the cluster you wish to edit.
3. Select Modify.
4. Expand the Additional configuration section.
5. For Database port, set the value to something other than the known port number.

In Terraform -

1. In the aws_rds_cluster resource, set the value for 'port' to something other than the known port number.

References:
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_RDS_Configuring.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/rds_cluster