Mark scheduled runs with nothing to build as cancelled instead of successful

[marionbarker]

Problem

The scheduled weekly run checks for new commits and only builds when something changed (or when the monthly forced build is due). When there is nothing to build, the build jobs are skipped and the run still completes with a green check — indistinguishable at a glance from a successful build. Users who rely on the green status can believe they have a fresh build even when their last real build attempt failed.

Change

Copied the change from LoopFollow PR 705. See that PR for more information.

Status semantics after this change:

• green — a new build was made and uploaded to TestFlight
• cancelled (grey) — the repository was already up to date, nothing was built
• red — a build was attempted and failed

[marionbarker]

Test

✅ successful test

Configuration

Used docs-test organization

• set up new branch weekly-check-cancel-status from LoopKit/LoopWorkspace branch
• edited the cron time so it would fire soon
• observed that because there were no updates and it is not the selected week of month, the build was marked as cancelled as desired