feat: set GitHub actions integration ID for ruleset CI checks

[amustaque97]

Closes #2197

Summary

This PR configures repository rulesets only to accept CI status checks from GitHub Actions by setting the integration_id to 15368.

Changes

• Added GITHUB_ACTIONS_INTEGRATION_ID constant (value: 15368) with verification link
• Updated construct_ruleset() to use the GitHub Actions integration ID for required status checks

Verification

The integration ID was verified via the public GitHub API:

curl -s https://api.github.com/repos/rust-lang/rust/commits/HEAD/check-runs | grep -A 3 '"app"'

[github-actions]

Dry-run check results

[WARN  sync_team] sync-team is running in dry mode, no changes will be applied.
[INFO  sync_team] synchronizing crates-io
[INFO  sync_team] synchronizing github
[INFO  sync_team] 💻 Repo Diffs:
    📝 Editing repo 'rust-lang/bors':
      Rulesets:
          Branch protection for main

[marcoieni]

Thanks!
One small thing. The dry run in #2201 doesn't show the content of the diff. Can you fix it? 🙏

[amustaque97]

Now it should show something like below

        Rule: Required Status Checks
          Strict Policy: false
          Checks:
            - CI (GitHub Actions, integration_id: 15368)
            - test (GitHub Actions, integration_id: 15368)

[amustaque97]

I made a change here. I do remember I need to convert the macro into a general function. I will take it up in a separate PR. In this PR, I'm adding a check for a clear description. If there are no changes, it must print.

Ruleset for main
        No changes

instead of just printing

Ruleset for main