readd dkim key for mail domain

tf-stage1/archlinux.tf

@@ -535,6 +535,14 @@ resource "hetznerdns_record" "archlinux_org_mail_txt" {
   type    = "TXT"
 }
 
+resource "hetznerdns_record" "archlinux_org_domainkey_mail_txt" {
+  zone_id = hetznerdns_zone.archlinux.id
+  name    = "mail._domainkey"
+  ttl     = 600
+  value   = "\"v=DKIM1; k=rsa; \" \"p=MIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAwq23VERpAp07Xe9vTro38q7D8HzGSi4I+vS2ZWdGeGmr9/YQs6EmoiDUWdXbThCAPhSW6RLgG62XLxnjEj9LxwyeluHKI4eMq14shwcTeRNzyrz/bTqAQouVLe3PmUo6mHWJfd4Z7k7/Kv0nmEx9cqM+IIwOjsGN28e52OCvc7NZeRqEvAJtlsV1Ren0piFvw/cuOqzo3Xgk2O\" \"T1/6PoItIQm1AYTmDBjPHvUqSa/lyr6MQYpH2EeQa7HV0l+XZmYA/tRpUE9ixwZ7+mvixMumTDRMB7Pp+WqbqXQcDodrh0H5RzxBPv11KP+09qcCZo26iBZeRb9H0CU0glIFJLWIejBY/10mOtcs68Kop2rNz3mga/Pxj9JGWndkjmLSscyPjjySHy/kakAqSafijq74ysA8nKx+MRnZYzqAwtn8sk8MF80mTZuMvHgzUn7fbG2bxVF7hc\" \"nD80OjlD+gXrl1MmiO5QfGPhsnx9SI/Bp3vo5rLayBTRCWv7QsQeU2hWi0wC/l2aG50apdPG0FJdrIQHicjx5zW+fWISbHRE3VwCI1oVejnl1E6XYmcrgeWG8O+iukfPYzEWiJ5BY8uk3bO75dFqaFH0yU7hdsC+yk+9+ZQDZKHcc0jum7C3U8SdW27af8/DkjAyoDn0g0Cj6N2QWDbZmHJfD7tY6O6Qpm8CAwEAAQ==\" "
+  type    = "TXT"
+}
+
 resource "hetznerdns_record" "archlinux_org_dmarc_txt" {
   zone_id = hetznerdns_zone.archlinux.id
   name    = "_dmarc"