You could use `opening_hours=closed` (or, probably less good, `operational_status=closed`).
You could also add a `note=` tag to let other mappers know why you've used this rather than `disused:amenity=pub`, and perhaps also a `fixme=` or OSM note to remind you/others to come back and survey it!
Please don't change the name tag - the name of the pub is not "temporarily closed" and there are other consumers that use name tags, e.g. geocoders, routers and many forms of spatial analysis.