Bug with checking winning condition in columns

[grainnecasey]

There is a bug checking winning condition in columns in this project. The following state will not be counted as a winning state even though it has been won by both players at this point (player 1 in col 0 and player 2 in col 4):
[[ 0 0 -1 0 0 0 0]
[ 0 0 -1 0 0 0 1]
[ 1 1 1 -1 -1 0 -1]
[ 1 -1 -1 1 -1 0 1]
[ 1 -1 1 1 -1 1 -1]
[ 1 -1 1 1 -1 1 -1]]

The following is the corrected column checking code, as I do not have permissions to create a PR on this repo:

			for row in range(self.board_shape[0] - self.win_condition - 1):
				column = self.__board[:, col]
				winning_set = column[row:row+self.win_condition]
				value = sum(winning_set)
				if abs(value) == self.win_condition:
					return True```