By Sarah N. Lynch WASHINGTON (Reuters) -A member of the far-right Proud Boys, Jeremy Bertino, pleaded guilty on Thursday to a charge of seditious conspiracy over his role in the Jan. 6, 2021, attack on the U.S. Capitol, making him the first member of the group to do so. Six other members, including former Proud Boys Chairman Enrique Tarrio, are due to stand trial beginning in December on charges including seditious conspiracy, which carries a potential prison sentence of up to 20 years. Bertino also pleaded guilty to a gun charge. “Guilty, your honor,” Bertino said when asked if he was pleadin…