Target Corp. has announced a fresh lineup of perks and promotions for the back-to-school season at a time when parents and teachers are feeling the squeeze of inflation. The retailer has expanded the college student discount to 20% with a Target Circle membership. And the Teacher Prep Event has been extended by nearly six weeks, from July 17 through September 10, offering 15% off school supplies and other merchandise. Tax-free weekends are returning, and the retailer is highlighting brands, including its own labels, as an…