[ruby/rdoc] Drop the support for 2.5 or earlier because of CVE-2021-31799
https://github.com/ruby/rdoc/commit/26136138aa
[ruby/rdoc] Drop the support for 2.5 or earlier because of CVE-2021-31799
https://github.com/ruby/rdoc/commit/26136138aa