Add turquoise.fyi as an ACME mail domain

Turquoise.fyi is owned by MostlyTurquoise, who we are hosting mail for.
Adding it as a mail domain will make us fetch certificates for it.

Change-Id: I4271f2efcff944d51f9bf4774d9e3b6ed6a1548d
Reviewed-on: https://git.clicks.codes/c/Clicks/NixFiles/+/207
Tested-by: Skyler Grey <minion@clicks.codes>
Reviewed-by: Samuel Shuert <coded@clicks.codes>
diff --git a/modules/common/mailcow.nix b/modules/common/mailcow.nix
index 7fa0b93..9073d56 100644
--- a/modules/common/mailcow.nix
+++ b/modules/common/mailcow.nix
@@ -7,6 +7,7 @@
     "starrysky.fyi"
     "a.starrysky.fyi"
     "thecoded.prof"
+    "turquoise.fyi"
   ];
   mailACMEHosts = [
     "mail.clicks.codes"