rulesets: log when default fields change

[marcoieni]

Fix #2376

I also convert crates.io-index-archive to prove that this PR works. In fact, the dry run now shows prevent-creation = false

[github-actions]

Dry-run check results

[WARN  rust_team::sync] sync-team is running in dry mode, no changes will be applied.
[INFO  rust_team::sync] synchronizing crates-io
[INFO  rust_team::sync] synchronizing github
[INFO  rust_team::sync] 💻 Repo Diffs:
    📝 Editing repo 'rust-lang/crates.io-index-archive':
      Branch Protections:
          main
            Deleting branch protection
          snapshot-*
            Deleting branch protection
      Rulesets:
          Creating 'snapshot-*'
            Include Branches: ["refs/heads/snapshot-*"]
            Require pull requests: false
            Restrict creations: false
          Creating 'main'
            Include Branches: ["refs/heads/main"]
            Require pull requests: false

[ubiratansoares]

This additional logging definitely helps 🙂