A Wausau bank and a Fitchburg man filed a class-action lawsuit Thursday against retail giant Target over the security breach late last year that affected millions of its customers. The lawsuit, filed in U.S. District Court in Madison, is the first of its kind to be filed in Wisconsin among a national wave of lawsuits against Target over the breach, in which hackers stole data about customers’ debit and credit cards that could be used by thieves to steal from Target customers.