The zone_id variable is added to the ses module to allow the module to
be used with different Route53 zones. The variable is used in the
aws_route53_record resource to set the zone_id attribute. The
aws_route53_zone data source is removed from the module and the zone_id
attribute is set directly. The count attribute is added to the
aws_route53_record resource to allow for multiple DKIM records to be
created.
