Jack Diemar hasn’t always been ‘all-in’ on cycling. But he is now — and he’s on a tear. The 18-year-old Eagle biker will represent the U.S. at the 54th annual Tour de l’Abitibi in Val-d’Or, Quebec next week. Roughly international 150 riders will take part in the 7-day, 667-kilometer stage race, which is the only UCI Junior Nationals Cup circuit event held in North America. “I’m super excited for it and seeing what opportunities come with it,”…