Update scipy version requirement
d9263987 on a stock Ubuntu 18.04.
gpaw/point_groups/groups.py:3: in <module>
from scipy.spatial.transform import Rotation
E ModuleNotFoundError: No module named 'scipy.spatial.transform'
It looks like this module has been added to scipy 1.2.0 https://github.com/scipy/scipy/commit/95296e4017ec32a516bf4932569ec5965f3917a2#diff-c5dec40f7f2f5604ff772dc53d741c1c0435320da54c267032fddf2ed3c72085 and Ubuntu 18.04 has 0.19.1.