An increasing number of U.S. athletes and sponsors are teaming up to embrace hot-button social justice issues and actively court controversy, following the high-profile trail blazed by Nike and former National Football League quarterback Colin Kaepernick.Is this a short-term trend or the beginning of a new era in sports marketing?Procter & Gamble, through its Secret women’s deodorant brand, has partnered with the U.S. women’s national soccer team to promote gender equality in sports, especially equal pay …