Updated Renovate workflow cron offset and timeout (#28196)

ref https://linear.app/ghost/issue/PLA-48

First day on `0 * * * *` surfaced two issues:

1. **GitHub Actions dropped every even-hour tick.** Since hourly landed,
every UTC even hour (00, 02, 04, 06, 08, 10) failed to fire; only odd
hours started runs. GH's docs flag the top of every hour as the worst
scheduler-delivery window. `17 * * * *` puts us off the contended slot.
2. **30m timeout was firing on real work.** Most runs hit
`timeout-minutes: 30` mid-rebase or mid-lockfile-maintenance across the
current 29-PR backlog. Raising to 45 lets catch-up cycles finish; can
drop back to 30 once the queue steadies.