Pretty-slack-notify fails since around November 1st, 2017

[Kotoriii]

All my projects fail to notify on build success / failure in the pretty-slack-notify after-step.
This is where it fails:

Bundle complete! 112 Gemfile dependencies, 282 gems now installed.
Bundled gems are installed into `/pipeline/cache/bundle-install`
bundler: failed to load command: /pipeline/pretty-slack-notify-9d35dd43-0865-424e-baed-919999a73905/run.rb (/pipeline/pretty-slack-notify-9d35dd43-0865-424e-baed-919999a73905/run.rb)
LoadError: cannot load such file -- slack-notifier
  /pipeline/pretty-slack-notify-9d35dd43-0865-424e-baed-919999a73905/run.rb:3:in `require'
  /pipeline/pretty-slack-notify-9d35dd43-0865-424e-baed-919999a73905/run.rb:3:in `<top (required)>'

[shibukk]

@Kotoriii I tried this and I could fix.

build:
    after-steps:
        - install-packages:
            packages: ruby
-       - wantedly/pretty-slack-notify:
+       - pasonatquila/pretty-slack-notify:
            webhook_url: $SLACK_WEBHOOK_URL

FYI:
pasonatquila@f247cb3