zsteg: Update gems and add missing bundler updater.

pkgs/by-name/zs/zsteg/Gemfile.lock

@@ -2,12 +2,12 @@ GEM
   remote: https://rubygems.org/
   specs:
     forwardable (1.3.3)
-    iostruct (0.0.5)
-    prime (0.1.2)
+    iostruct (0.5.0)
+    prime (0.1.3)
       forwardable
       singleton
     rainbow (3.1.1)
-    singleton (0.2.0)
+    singleton (0.3.0)
     zpng (0.4.5)
       rainbow (~> 3.1.1)
     zsteg (0.2.13)
@@ -22,4 +22,4 @@ DEPENDENCIES
   zsteg
 
 BUNDLED WITH
-   2.4.13
+   2.6.6

pkgs/by-name/zs/zsteg/gemset.nix

@@ -14,10 +14,10 @@
     platforms = [ ];
     source = {
       remotes = [ "https://rubygems.org" ];
-      sha256 = "1z3vnb8mhzns3ybf78vlj5cy6lq4pyfm8n40kqba2s33xccs3kl0";
+      sha256 = "0pswyhjz9d90bympsz6s0rgv24b8nrd4lk5y16kz67vdw6vbaqbp";
       type = "gem";
     };
-    version = "0.0.5";
+    version = "0.5.0";
   };
   prime = {
     dependencies = [
@@ -28,10 +28,10 @@
     platforms = [ ];
     source = {
       remotes = [ "https://rubygems.org" ];
-      sha256 = "1973kz8lbck6ga5v42f55jk8b8pnbgwp9p67dl1xw15gvz55dsfl";
+      sha256 = "1qsk9q2n4yb80f5mwslxzfzm2ckar25grghk95cj7sbc1p2k3w5s";
       type = "gem";
     };
-    version = "0.1.2";
+    version = "0.1.3";
   };
   rainbow = {
     groups = [ "default" ];
@@ -48,10 +48,10 @@
     platforms = [ ];
     source = {
       remotes = [ "https://rubygems.org" ];
-      sha256 = "0qq54imvbksnckzf9hrq9bjzcdb0n8wfv6l5jc0di10n88277jx6";
+      sha256 = "0y2pc7lr979pab5n5lvk3jhsi99fhskl5f2s6004v8sabz51psl3";
       type = "gem";
     };
-    version = "0.2.0";
+    version = "0.3.0";
   };
   zpng = {
     dependencies = [ "rainbow" ];

pkgs/by-name/zs/zsteg/package.nix

@@ -1,12 +1,18 @@
-{ lib, bundlerApp }:
+{
+  lib,
+  bundlerApp,
+  bundlerUpdateScript,
+}:
 
-bundlerApp {
+bundlerApp rec {
   pname = "zsteg";
 
   gemdir = ./.;
 
   exes = [ "zsteg" ];
 
+  passthru.updateScript = bundlerUpdateScript pname;
+
   meta = with lib; {
     description = "Detect stegano-hidden data in PNG & BMP";
     homepage = "http://zed.0xff.me/";