Revert "ci: avoid warnings from setup-ruby-ref"

[flavorjones]

This reverts commit a81343b.

What problem is this PR intended to solve?

Ruby-head on windows is failing. It's not clear to me why

The first failure was here, with an error message indicating it might have been a server-side problem, but I recently introduced a81343b to quash warnings and a different failure is now being raised, which seems to be packages not being found when enabling system libraries, and a segfault when using packaged libraries.

Here I'm just experimentally unwinding that change to see if I can learn what's going wrong.

[flavorjones]

Editor's note: the ruby-head builds went green on this branch. Now I'm re-running https://github.com/sparklemotion/nokogiri/actions/runs/1114254585 on main to double-check that there was anything wrong under our control in the first place 🤷

[flavorjones]

Editor's note: re-running main still fails in interesting ways, so I guess this config is needed even though I don't understand what it's doing.

@MSP-Greg If you get a moment, can you help me understand why this config is needed and what it's doing? And why it's emitting warnings?

        setup-ruby-ref: MSP-Greg/ruby-setup-ruby/00-win-ucrt

Successful run with this config showing warnings: https://github.com/sparklemotion/nokogiri/actions/runs/1117283592

Failing runs without this config: https://github.com/sparklemotion/nokogiri/actions/runs/1114254585

[flavorjones]

Ah, I get it, that's used to set up ruby based on https://github.com/MSP-Greg/ruby-setup-ruby/blob/00-win-ucrt/dist/index.js

OK, all good, merging.