Support Ruby 3.3.7

[degwinthegreat]

Why?

This PR relaxes the upper Ruby version constraint to support Ruby 3.3.7

scimaenaga-1.0.5 requires ruby version <= 3.3.6, >= 2.5.9, which is incompatible
with the current version, 3.3.7

https://www.ruby-lang.org/en/news/2025/01/15/ruby-3-3-7-released/

What?

Relax required_ruby_version

[mtakeda15]

Thank you!!

[mtakeda15]

It seems Ruby 3.3.7 is not supported yet. I guess we'll have to wait.
https://github.com/ruby/setup-ruby/blob/master/ruby-builder-versions.json

[degwinthegreat]

Thank you for your review!

The failing test seems to be related to this issue
actions/runner-images#11279

From this test, ubuntu seemed to have gone up from 22.04.5 to 24.04.1.

Log from this run

> Set up job
Current runner version: ‘2.321.0’
Operating System
  Ubuntu
  24.04.1
  LTS

https://github.com/StudistCorporation/scimaenaga/actions/runs/12787027869/job/35694697865

Log of last successful run.

> Set up job

Current runner version: ‘2.320.0’
Operating System
  Ubuntu
  22.04.5
  LTS

https://github.com/StudistCorporation/scimaenaga/actions/runs/11738822720/job/32702082566

Apparently a fixed version was released two days ago, but how to pull this image I have no idea.
https://github.com/actions/runner-images/releases/tag/ubuntu24%2F20250113.1

[mtakeda15]

I fixed CI: #60

thanks!