"Create Bullet Train Upgrade PR" GHA fails on ruby upgrades

[jagthedrummer]

Not sure how we should handle this, but here's the situation.

On the demo site I tried to run the upgrade action and it failed due to a ruby version mismatch. In that repo the .ruby-version file says 3.2.2. So when the setup-ruby action runs it installs ruby 3.2.2. Then the workflow pulls down changes from the starter repo, where .ruby-version says 3.3.0. Then when we try to fix conflicts in Gemfile.lock we have to run bundle install and it fails because the wrong version of ruby is installed on the action runner.

Going to update the demo site by hand to get over this hump.