feat: require pollora/hook 2.0

[ogorzalka]

Step 4 of the pollora/schedule plan, framework side. Needs pollora/hook v2.0.0 (released) and pollora/schedule v0.1.2.

• pollora/hook ^2.0: asynchronous actions queue through the WP-Cron and Action Scheduler drivers of pollora/schedule. Async\Drivers\WpCronDriver and ActionSchedulerDriver are gone with no alias; the framework never used them. ->async(), #[Async], Async::fake(), via() and their options are unchanged, work queued by 1.x runs once the upgrade is in, and the queue driver (QueueDriver) is untouched.
• AsyncInspector::overdueCronEvents() no longer counts the events Action Scheduler keeps: the cron option has indexed them, with a driver key, since feat: choose the scheduling driver, list and migrate scheduled events #470, so pollora:doctor would have called them overdue WP-Cron events.

use_laravel_scheduler and QueueDriver stay for step 5.

Checked on pollora-test with hook 2.0 linked: 3 messages queued under 1.4.1 run under 2.0, and with the site on Action Scheduler via('wp-cron') stays an unmarked WP-Cron event.