paperkey: 1.5 -> 1.6

Semi-automatic update generated by
https://github.com/ryantm/nixpkgs-update tools. This update was made
based on information from
https://repology.org/metapackage/paperkey/versions

pkgs/tools/security/paperkey/default.nix

···
 
 stdenv.mkDerivation rec {
   name = "paperkey-${version}";
-  version = "1.5";
+  version = "1.6";
 
   src = fetchurl {
     url = "http://www.jabberwocky.com/software/paperkey/${name}.tar.gz";
-    sha256 = "1prd2jaf4zjad3xhv160hmi5n408ssljfg7iz90jxs9w111pjwy4";
+    sha256 = "1xq5gni6gksjkd5avg0zpd73vsr97appksfx0gx2m38s4w9zsid2";
   };
 
   postPatch = ''