Catch stable channel more precisely

[sagudev]

Add cron that will catch stable releases more precisely.

[sagudev]

This is best-effort anyway, it doesn't cost anything, we just try to do our best to get stable versions sooner.

[iterion]

Instead of bikeshed over the exact timing maybe we could just run this multiple times per day? It's a bummer to wait 24h no matter when the new rust release ships. And, action runs are cheap overall especially for open projects.

[iterion]

Thank you @oxalica!!

[Fuuzetsu]

Thank you! We are in JST timezone so we usually end up seeing a release in morning and then having to wait few hours to use it...