Moved from removed OkJson to MultiJson

[twolfson]

As of March 7 2014, Heroku::OkJson no longer exists.

heroku/legacy-cli@132df5c#diff-0efbd84cf2791121a9643b549a423f99

heroku/legacy-cli@24751ef#diff-0efbd84cf2791121a9643b549a423f99

This has been causing errors in the ranger plugin. To repair this, we are moving to MultiJson which is the new library that Heroku is using for its json_decode:

https://github.com/heroku/heroku/blob/v3.26.0/lib/heroku/helpers.rb#L211-L215

In this PR:

• Move all Heroku::OkJson references to their MultiJson equivalent

[twolfson]

For anyone interested in using this module in the interim, it can be installed via:

# Install to plugin directory and checkout fixed branch
heroku plugins:install git@github.com:underdogio/heroku-ranger.git
cd ~/.heroku/plugins/heroku-ranger
git checkout bug/okjson.missing

or via symlink:

# Clone the repo
git clone git@github.com:underdogio/heroku-ranger.git
cd heroku-ranger/

# Navigate to the fixed branch
git checkout bug/okjson.missing

# Symlink it to the corresponding directory
ln -s "$HOME/github/heroku-ranger" "$HOME/.heroku/plugins/heroku-ranger"

[twolfson]

It has almost been 2 months since the opening of this PR. Any idea of when we can get it merged in?

[shayfrendt]

@twolfson So sorry for the delay here. Not quite sure how I missed the notification for this pull.

Thanks for the contribution, this looks great. ✨