You are given an `m x n` grid of cells, where each cell is either `0` for inactive or `1` for active. All cells update simultaneously according to these rules: - An active cell with fewer than two active neighbors becomes inactive. - An active cell with two or three active neighbors remains active. - An active cell with more than three active neighbors becomes inactive. - An inactive cell with exactly three active neighbors becomes active. Each cell has up to eight neighbors: horizontal, vertical, and diagonal adjacent cells. Implement a function that modifies the input grid in place to represent the next state of the grid. You may not allocate another `m x n` grid, but you may use constant extra space besides loop variables.