Jenny Han’s bestselling Summer trilogy is the latest to get the television treatment, and our summer’s already looking brighter. “The Summer I Turned Pretty,” is a coming-of-age romantic drama that follows Isabel “Belly” Conklin (Lola Tung) during her family’s annual summer vacation to the idyllic Cousins Beach. When the nearly-16-year-old Belly returns to the place, she finds herself at the center of a complicated love triangle involving her childhood friends, brothers Jeremiah (Gavin…