points_set_values does not work for a datetime coordinate

In GitLab by @jdelsman on Aug 31, 2020, 17:03

Trying to set point_values in a (time,layer,y,x) dataarray, I get the following error:

Traceback (most recent call last):
File "", line 7, in
File "c:\Users\delsman\Documents\imod-python\imod\select\points.py", line 241, in points_set_values
inside = points_in_bounds(da, **points)
File "c:\Users\delsman\Documents\imod-python\imod\select\points.py", line 62, in points_in_bounds
_, xmin, xmax = imod.util.coord_reference(da_x)
File "c:\Users\delsman\Documents\imod-python\imod\util.py", line 341, in coord_reference
dxs = np.diff(x.astype(np.float64))
ValueError: could not convert string to float: '2051-10-01 00:00:00'

Start in imod/select/points.py at points_set_values and points_in_bounds, then inspect imod/util.py at coord_reference, where the traceback shows datetime values are converted to float. Reproduce the failure with a (time,layer,y,x) dataarray and confirm that setting point values with a datetime coordinate completes without the conversion error.