consider removing support for older rubies

[flavorjones]

It's getting hard to support old rubies, see failing test suites here related to setup-ruby and bundler versions:

https://github.com/flavorjones/mini_portile/actions/runs/3771621986/jobs/6412111557

I'd like to consider dropping support for ruby < 2.6 in the next minor release.

[halostatue]

Still worth considering. minitar v1 has been released and only supports Ruby 3.1 or later. There shouldn't be any other changes required since you are not using the Archive::Tar namespace.

[flavorjones]

@halostatue Thanks for that context! I've only not-removed support because it hasn't bitten me since I opened this ticket. 🍀 It's only a matter of "when" we drop support, not "if". ❤️

[halostatue]

Yeah. I’m getting ready to go through a similar upgrade process for most of my maintained gems, although I probably won't be cutting them "hard" like I have done with minitar (that is, when I cut mime-types 4, I will continue to maintain mime-types 3 for some time to come, but new features will not show up in mime-types 3; same with diff-lcs 2 vs diff-lcs 1).

I need to open a discussion on ruby-core to get some advice from yjit developers so I can examine these for ways to ensure that these gems are easier to optimize.