What would the attack modifier be for an unarmed strike while wildshaped?

I know from a well voted for answer in Is a Wild Shape attack considered an unarmed strike? that it is possible for a druid to make an unarmed strike while wildshaped, just instead of the beast’s normal damage you would deal 1+STR (or otherwise for a monk or druid with Tavern Brawler), but what would the attack modifier be? A character is proficient in their unarmed strikes, so would they use proficiency bonus + strength modifier? Or would it just be straight strength modifier because they have no proficiency bonus, as their game statistics were replaced by the beast’s?