Improve Ruby guide

[dentarg]

Why:

• The wildcard doesn't work in setup-ruby: Wildcard character not respected ruby/setup-ruby#251
• Update to the latest version of setup-ruby: https://github.com/ruby/setup-ruby/releases/tag/v1.97.0

Closes [issue link]

What's being changed:

Check off the following:

• I have reviewed my changes in staging (look for "Automatically generated comment" and click Modified to view your latest changes).
• For content changes, I have completed the self-review checklist.

Writer impact (This section is for GitHub staff members only):

• This pull request impacts the contribution experience
  • I have added the 'writer impact' label
  • I have added a description and/or a video demo of the changes below (e.g. a "before and after video")

[dentarg]

• Update to the latest version of setup-ruby: https://github.com/ruby/setup-ruby/releases/tag/v1.97.0

I did this because the previous version referenced, v1.75.0 (ruby/setup-ruby@477b21f), does not support Ruby 3.1.