Explore creating a Ruby 3.3.0-preview build container

[flavorjones]

The primary goal is to be proactive about some of the work we'll need to do for a 3.3.0-final build container.

A secondary goal would be to allow advanced users and teams to precompile gems for ruby-head or ruby-3.3.0-preview1.

At this point I'm not proposing that we formally support Ruby prereleases, but I would like to the weekly "snapshot" builds provide this for experimentation and feedback.

[flavorjones]

See #105 for draft PR.

[flavorjones]

Merged #105, next snapshot build will ship with experimental support for 3.3.0 based on preview3

[flavorjones]

Kicked off CI on a Nokogiri branch to test the container from #105

• ext: ruby 3.3 support sparklemotion/nokogiri#3038

[flavorjones]

OK, Nokogiri is green, I'm going to close this and will cut a release candidate that supports 3.3.0-preview3