existing example returns an error like the following should you try to
run `terraform plan` against it:
Error reading config for aws_subnet[example]: data.aws_availability_zone.name_suffix: data variables must be four parts: data.TYPE.NAME.ATTR in:
${cidrsubnet(aws_vpc.example.cidr_block, 4, var.az_number[data.aws_availability_zone.name_suffix])}
This adds a singular data source in addition to the existing plural one.
This allows retrieving data about a specific AZ.
As a helper for writing reusable modules, the AZ letter (without its
usual region name prefix) is exposed so that it can be used in
region-agnostic mappings where a different value is used per AZ, such as
for subnet numbering schemes.