Use Ruby 3.3 for gh_pages build

[jeremyevans]

Hopefully this will fix the following error:

You have already activated uri 0.12.1, but your Gemfile requires uri 0.13.0. Since uri is a default gem, you can either remove your dependency on it or try updating to a newer version of bundler that supports uri as a default gem.

https://github.com/ruby/uri/actions/runs/10029934700/job/27718711665#step:5:38

[olleolleolle]

This got us to green, thank you!

[jeremyevans]

Unfortunately, this doesn't seem to have helped: https://github.com/ruby/uri/actions/runs/10030217373/job/27719279537

Maybe we need to explicitly update the bundler version?

[olleolleolle]

@jeremyevans What if you used '3.3.4' instead of the short-hand '3.3' when telling setup-ruby the version?

This was from the erroring build's Setup Ruby step:

Print Ruby version
  /opt/hostedtoolcache/Ruby/3.3.0-preview1/x64/bin/ruby --version
  ruby 3.3.0preview1 (2023-05-12 master a1b01e7701) [x86_64-linux]
  Took   0.02 seconds

[jeremyevans]

We could do that, but we really shouldn't have to. Something is broken in the tooling if 3.3 results in 3.3.0preview1 and not the latest 3.3 release.