Re-add support for ordered_by matcher for Mongoid 5 and older

[stim371]

The PR to support Mongoid 6 removed a conditional to select the correct
location for the Key class.

Fixes #214

Question for Maintainer

This PR fails a rubocop check for Class length. Curious if you'd like to try to golf the class or extend/ignore the rubocop check.

[dblock]

For rubocop just run rubocop -a ; rubocop --auto-gen-config, we only care about auto-correctable things.

[dblock]

Thanks for fixing this, will merge on green.

[stim371]

Thanks, @dblock . Should be all set!

[zedtux]

Thank you @stim371 ! 🎉

[zedtux]

@dblock will you release a new version of this gem soon?

[dblock]

I can, but this gem really could use some more maintainers. Maybe @stim371 wants to join? If yes what's your rubygems email, I'll grant you access.

[stim371]

@dblock I see a number of open issues that might be interesting to try to pick off, but I'm about to move away from mongoid (switching orgs), so I don't think I'd be a very active/invested maintainer for the long term.

[zedtux]

Lucky you are @stim371 😏

[dblock]

Thanks @stim371, no worries. Definitely looking forward to you contributions time permitting! Also MongoDB is great, I don't know what ya'll talking about :)