Run tests on Ruby 3.3, 3,4

[ohbarye]

Hi, this pull request just lets tests run on Ruby 3.3 and 3.4.

https://www.ruby-lang.org/en/news/2023/12/25/ruby-3-3-0-released/ https://www.ruby-lang.org/en/news/2024/12/25/ruby-3-4-1-released/

By the way, Ruby 3.0 or priors are already EOL. I wonder if required_ruby_version could be more later version.

https://www.ruby-lang.org/en/downloads/branches/