Add setproduct function to the bake HCL

[felipecrs]

As explained in the following link, it's a very useful function.

https://www.terraform.io/docs/configuration/functions/setproduct.html#finding-combinations-for-for_each

This is my use case:

function "create_tags" {
  params = [image_name]
  variadic_param = tags
  
  result = [
    for rt in setproduct(["docker.io", "ghcr.io"], tags):
        "${rt[0]}/${image_name}:${rt[1]}"
  ]
}

[crazy-max]

LGTM