Revert "Merge #188995: bundler: 2.3.20 -> 2.3.21"

Moving to staging branch, as it's a huge rebuild.

This reverts commit 6511d3f, reversing
changes made to cf40140.

pkgs/development/ruby-modules/bundler/default.nix

@@ -1,31 +1,14 @@
-{ lib, buildRubyGem, ruby, writeScript }:
+{ buildRubyGem, ruby }:
 
 buildRubyGem rec {
   inherit ruby;
   name = "${gemName}-${version}";
   gemName = "bundler";
-  version = "2.3.21";
-  source.sha256 = "sha256-+u3H/8Fno8U7ZMRj2me1DVvkOAR2HeWmjdo0TCG/0d4=";
+  version = "2.3.20";
+  source.sha256 = "sha256-gJJ3vHzrJo6XpHS1iwLb77jd9ZB39GGLcOJQSrgaBHw=";
   dontPatchShebangs = true;
 
-  passthru.updateScript = writeScript "gem-update-script" ''
-    #!/usr/bin/env nix-shell
-    #!nix-shell -i bash -p curl common-updater-scripts jq
-
-    set -eu -o pipefail
-
-    latest_version=$(curl -s https://rubygems.org/api/v1/gems/${gemName}.json | jq --raw-output .version)
-    update-source-version ${gemName} "$latest_version"
-  '';
-
   postFixup = ''
     sed -i -e "s/activate_bin_path/bin_path/g" $out/bin/bundle
   '';
-
-  meta = with lib; {
-    description = "Manage your Ruby application's gem dependencies";
-    homepage = "https://bundler.io";
-    license = licenses.mit;
-    maintainers = with maintainers; [anthonyroussel];
-  };
 }