Version 5.20 of the Terraform AWS provider is the first version
to offer the aws_sesv2_account_vdm_attributes resource, which we
require in this root module.

…role-tf-module

This is being done for testing purposes and can be reverted once
cisagov/terraform-state-read-role-tf-module#37 is merged.

VDM will show us some useful information about emails that bounced,
such as the diagnostic code indicating the reason for the bounce.

We don't care about the engagement metrics, since we don't care to
track if users click the attachments we send.

…ppression list

This will allow suppression list managers to get a suppressed
destination (which will include a message ID) and then get the
insights for that particular message.  This will allow the suppression
list managers to view, e.g., the diagnostic code associated with the
bounce.

This is something we should consider doing in the future, although I'm
not sure it could be done non-destructively.

This is issue #109.

…module

We can do this now that cisagov/terraform-state-read-role-tf-module#37
has been merged.