The Knicks have shored up the end of their roster. Jericho Sims, the 2021 second-round pick who climbed into the rotation by the end of last season, agreed to a three-year contract worth $6 million, a source confirmed Thursday. The final year is a team option. In an adjacent move, the Knicks agreed to sign this year’s second-round pick, guard Trevor Keels, to a two-way contract, a source confirmed. Sims was on a two-way contract last season. Feron Hunt, a 23-year-old wing, still occupies the team’s other two-way deal. The move to lock down Sims for multiple years was expected after he earned m…