Refactor: Extract to another workflows

[sue445]

Motivation

It is confusing when adding a new Ruby version because we have to add the same one to multiple jobs.

e.g. 26fa2d7e81e20127b1d0937756dece5b6483639d

So I refactored it by consolidating the matrix in one place

c.f.

• https://docs.github.com/en/actions/using-workflows/reusing-workflows
• https://github.blog/changelog/2021-11-24-github-actions-reusable-workflows-are-generally-available/

[sue445]

@unasuke What do you think for this patch?