Bump ruby/setup-ruby from 1.267.0 to 1.268.0

Bump ruby/setup-ruby from 1.267.0 to 1.268.0

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.267.0 to 1.268.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](https://github.com/ruby/setup-ruby/compare/d5126b9b3579e429dd52e51e68624dda2e05be25...8aeb6ff8030dd539317f8e1769a044873b56ea71)

---
updated-dependencies:
- dependency-name: ruby/setup-ruby
  dependency-version: 1.268.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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