Get output (convert) into resource as string - terraform

Question

My goal is to have something like a common.tfvars file eg:
users = {
"daniel.meier" = {
path = "/"
force_destroy = true
tag_email = "foo#example.com"
github = "dme86"
}
"linus.torvalds" = {
path = "/"
force_destroy = true
tag_email = "bar#example.com"
github = "torvalds"
}
}
Via data you'll be able to retrieve informations about the github accounts:
data "github_user" "this" {
for_each = var.users
username = each.value["github"]
}
Output of ssh keys is also possible:
output "current_github_ssh_key" {
value = values(data.github_user.this).*.ssh_keys
}
But how can i get the SSH keys from output into a resource like:
resource "aws_key_pair" "deployer" {
for_each = var.users
key_name = each.value["github"]
public_key = values(data.github_user.this).*.ssh_keys
}
If i'm trying like in this example terraform errors
Inappropriate value for attribute "public_key": string required.
which makes sense, cause the keys are a list AFAIK - but how to convert this correctly?
Output looks like this:
Changes to Outputs:
+ current_github_ssh_key = [
+ [
+ "ssh-rsa AAAAB3NzaC1yc2EAAAAD(...)ElQ==",
],
+ [
+ "ssh-rsa AAAAB3NzaC1yc2EAAGVD(...)TXxrF",
],
]
If you want to test this code you have to include a github token for your provider like:
provider "github" {
token = "123456"
}