The federal investigation into the Capitol riot reached deeper into the Charlotte area on Thursday when a Gaston County man pleaded guilty to taking part in a Proud Boys seditious conspiracy to block the presidential transfer of power. Jeremy Bertino, 43, of Belmont, a leader in the militant right wing group, becomes the third North Carolinian to plead guilty to the sprawling prosecution’s most serious charge — a conspiracy to use force to oppose the government of the United States. The charge carries a maximum penalty of 20 years in prison and a $250,000 fine. As part of his plea deal with fe…