Fix bundle outdated with both --groups and --parseable flags

[markburns]

What was the end-user or developer problem that led to this PR?

The bundle outdated command blows up when combining --groups and --parseable options

What is your fix for the problem, implemented in this PR?

Add a spec to replicate and fix the argument passed to the print_gems method.

Explanation: it seems this behaviour was untested and broken.

Fixes #6147.

Make sure the following tasks are checked

• Describe the problem / feature
• Write tests for features and bug fixes
• Write code to solve the problem
• Make sure you follow the current code style and write meaningful commit messages without tags

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[deivid-rodriguez]

Thanks @markburns! Other than the lint error, this seems fine. I'll merge this as soon as the lint error is fixed ❤️

[markburns]

Thanks @deivid-rodriguez. Should be fixed now.

Ironically found it tricky setting up rubocop due to gem dependency issues. Just manually installed the dependencies now to get working locally. Curious if there's any way to use bundler to build bundler.

[deivid-rodriguez]

We do use a Gemfile to keep our development dependencies, and use Bundler to install them under the hood. You should run rake setup to install them. Did you run into any issues with that? I did have some issues with RSpec activation recently, but not with RuboCop.

[markburns]

@deivid-rodriguez I see, yes that works fine now. I think it's a little unclear as that's at the top level of rubygems.
Whereas there's no mention of that at the /bundler level.

I went
from here -> to here -> then here

and I managed to avoid seeing rake setup

I would do a PR to improve the docs, but I am not sure I'm familiar enough yet with the process and setup to suggest it.

[simi]

I would do a PR to improve the docs, but I am not sure I'm familiar enough yet with the process and setup to suggest it.

To update docs just find out related "ronn" file (maybe this one https://github.com/rubygems/rubygems/blob/master/bundler/lib/bundler/man/bundle-outdated.1.ronn?), do the change, render it to the man format (using rake man:build in bundler subfolder) and open PR with both files updated.

[deivid-rodriguez]

Thanks for the feedback and for this PR @markburns. I opened #6154 to improve our development setup docs.