Upload fails if schedule:timezone is used in a workflow

[martincostello]

If the new timezone key is added to a schedule, the action fails to upload results:

2026/03/30 18:57:25 error sending scorecard results to webapp: http response 400, status: 400 Bad Request, error: {"code":400,"message":"workflow verification failed: unable to parse github workflow: [:9:7: expected \"cron\" key for element of \"schedule\" section but got \"timezone\" [syntax-check]]"}

Example commit that causes this error: martincostello/Pseudolocalizer@acfde34