etc: add known hash for /etc/shells

doc/known-files/9d5aa72f807091b481820d12e693093293ba33c73854909ad7b0fb192c2db193

@@ -0,0 +1,11 @@
+# List of acceptable shells for chpass(1).
+# Ftpd will not allow users to connect who are not using
+# one of these shells.
+
+/bin/bash
+/bin/csh
+/bin/dash
+/bin/ksh
+/bin/sh
+/bin/tcsh
+/bin/zsh

modules/system/shells.nix

@@ -41,5 +41,9 @@ in
       ${concatStringsSep "\n" cfg.shells}
     '';
 
+    environment.etc."shells".knownSha256Hashes = [
+      "9d5aa72f807091b481820d12e693093293ba33c73854909ad7b0fb192c2db193"  # macOS
+    ];
+
   };
 }