Default postgresql module to using UTF8 encoding

Signed-off-by: magic_rb <magic_rb@redalder.org>

Author: MagicRB

modules/services/postgresql.nix

@@ -105,7 +105,10 @@ in
 
       initdbArgs = lib.mkOption {
         type = with lib.types; listOf str;
-        default = [ ];
+        default = [
+          "-E"
+          "UTF8"
+        ];
         example = [
           "--data-checksums"
           "--allow-group-access"