Include Sid field for findings

[agentreno]

This field can also fail late (at terraform apply time) if it's not formatted correctly and Parliament can warn about this - it just needs including in your field mappings.

Tested manually on:

data "aws_iam_policy_document" "example" {
    statement {
        sid = "foo bar"
        actions = [
            "s3:GetObject",
        ]
        resources = [
            "arn:aws:s3:::mybucket/*",
        ]
    }
}

test.tf
INVALID_SID
Details:
  {'Effect': 'Allow', 'Sid': 'foo bar', 'Action': ['s3:GetObject'], 'Resource': ['arn:aws:s3:::mybucket/*']}
Location:
  {'filepath': None}