Currently, the bundle update --ruby is incorrectly synced on Homebrew/.github's .ruby-version rather than Homebrew/brew's.

This is because the flow goes like this:

• .ruby-version on .github is 3.3.2
• setup-ruby installs 3.3.2
• sync script run under 3.3.2
• 3.3.3 copied from Homebrew/brew to repo
• bundler install --ruby called but the ruby installed is still 3.3.2 as we didn't run setup-ruby again
• update to lockfile doesn't happen (until after the .ruby-version update PR is merged in Homebrew/.github)

This fixes it by doing an initial pre-sync of the ruby version prior to starting the sync script. Bundler will then operate under that new Ruby.