code mistake in velocity compute

[ChenChenGith]

argoverse-forecasting/utils/social_features_utils.py

Lines 43 to 48 in 27696a1

	vel_x, vel_y = zip(*[(
	x_coord[i] - x_coord[i - 1] /
	(float(timestamp[i]) - float(timestamp[i - 1])),
	y_coord[i] - y_coord[i - 1] /
	(float(timestamp[i]) - float(timestamp[i - 1])),
	) for i in range(1, len(timestamp))])

Missing '()' in x_coord[i] - x_coord[i - 1] and y_coord[i] - y_coord[i - 1], which leads to huge velocity. Vehicles will always be judged to be not stationary.