Consider to cut new release for next preview release of Ruby

[hsbt]

👋 Hi, we have a plan to next preview release of Ruby after next week.

The master branch of ruby/ruby still points development version of irb. It's nice to move the release version like 1.15.3.

https://github.com/ruby/ruby/blob/master/gems/bundled_gems#L44

I can release that if you are busy. Please let me know anything.

@tompng Could you also consider to release stable version of https://github.com/ruby/repl_type_completor?

[tompng]

IRB 1.15.3 and ReplTypeCompletor 0.1.12 released
#1134
ruby/repl_type_completor#66

[hsbt]

🙏 Thanks always.