feat(teal): Permit headscale for mostlyturquoise

Mostlyturquoise needs access to our silverbullet instance, which
requires headscale.

Change-Id: Id78aeb9f5f5c013b3630a258c400bd70dcb5b16a
Reviewed-on: https://git.clicks.codes/c/Infra/NixFiles/+/862
Tested-by: Skyler Grey <minion@clicks.codes>
Reviewed-by: Skyler Grey <minion@clicks.codes>
diff --git a/systems/x86_64-linux/teal/default.nix b/systems/x86_64-linux/teal/default.nix
index f3ea080..8123543 100644
--- a/systems/x86_64-linux/teal/default.nix
+++ b/systems/x86_64-linux/teal/default.nix
@@ -121,6 +121,7 @@
               "minion"
               "pineafan"
               "zanderp25"
+              "mostlyturquoise"
             ];
             groups."group:friends" = [
               "sirdigalot"