Switch to s3krit/await-status-action

Turns out Sibz/await-status-action looks at /ref/statuses, which lists ALL statuses (i.e., if you send a pending and a failure for the same context, it will see both and assume the job is still pending.). I forked and point at /ref/status, which shows a combined summary of each status (i.e., only ever shows the most recent status of a single context).