modify readme

Author: neka-nat

README.md

@@ -77,6 +77,8 @@ from probreg import cpd
 # load source and target point cloud
 source = o3.io.read_point_cloud('bunny.pcd')
 target = copy.deepcopy(source)
+source.remove_non_finite_points()
+target.remove_non_finite_points()
 # transform target point cloud
 th = np.deg2rad(30.0)
 target.transform(np.array([[np.cos(th), -np.sin(th), 0.0, 0.0],