Well, what I assume they will/would do is essentially make it unlawful to play sporting events within a particular time-frame, or until they advise it is safe to do so. They wouldn't 'cancel' the league for a number of reasons, not least that they might be assuming some responsibility, or rendering themselves liable for some or all of the financial losses (i.e. clubs sue the PL and PL sues the state). They won't legislate for anything specific that deals with private contractual rights or obligations, rather they'll just put in place measures that constructively might have the same effect, without putting them in the crosshairs.