add ci conclusion job for simpleinfra

[marcoieni]

added in rust-lang/simpleinfra#1126

[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/simpleinfra':
      Rulesets:
          Updating 'master'
            Required status checks: GitHub Actions (JS) (integration_id: 15368), Rust projects (integration_id: 15368), Terraform configuration (integration_id: 15368) => CI (integration_id: 15368)