asciidoctor: add update.sh for dependency updates

pkgs/tools/typesetting/asciidoctor/default.nix

@@ -1,10 +1,10 @@
-{ stdenv, lib, bundlerApp, ruby
+{ stdenv, lib, bundlerApp, ruby, bundix, mkShell
   # Dependencies of the 'mathematical' package
 , cmake, bison, flex, glib, pkgconfig, cairo
 , pango, gdk_pixbuf, libxml2, python3, patchelf
 }:
 
-bundlerApp {
+bundlerApp rec {
   inherit ruby;
   pname = "asciidoctor";
   gemdir = ./.;
@@ -43,6 +43,12 @@ bundlerApp {
     };
   };
 
+  passthru.updateShell = mkShell {
+    buildInputs = (gemConfig.mathematical {}).buildInputs ++ [
+      bundix
+    ];
+  };
+
   meta = with lib; {
     description = "A faster Asciidoc processor written in Ruby";
     homepage = https://asciidoctor.org/;

pkgs/tools/typesetting/asciidoctor/update.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+rm gemset.nix Gemfile.lock
+nix-shell ../../../.. -A asciidoctor.updateShell --run '
+  bundix -m --bundle-pack-path $TMPDIR/asciidoctor-ruby-bundle
+'
+rm -r .bundle