fix bad dependency

mne/transforms.py

@@ -12,7 +12,7 @@ from pathlib import Path
 import numpy as np
 from scipy import linalg
 from scipy.spatial.distance import cdist
-from scipy.special import sph_harm
+from scipy.special import sph_harm_y
 
 from ._fiff.constants import FIFF
 from ._fiff.open import fiff_open