Japanese tennis star, Naomi Osaka has become the world’s highest-paid female athlete, displacing US rival Serena Williams at the top of the list.   The 22-year-old also broke Maria Sharapova’s previous record for a female athlete which was set in 2015 when she totaled $29.7 million.   According to Forbes magazine, Osaka, a two-time Grand Slam champion, made £30.7m in prize money and endorsements over the past 12 months, setting a new record. That was £1.15m more than the amount earned by 38-year-old Williams. …