Applying theta transforms in ~matplotlib.projections.polar.PolarTransform and
~matplotlib.projections.polar.InvertedPolarTransform has been removed, and
the apply_theta_transforms keyword argument removed from both classes.
If you need to retain the behaviour where theta values
are transformed, chain the PolarTransform with a ~matplotlib.transforms.Affine2D
transform that performs the theta shift and/or sign shift.