NotImplementedError: 7 is unsupported for ndpi on Python 3.11 about opentile

[jesper-molin]

Thank you for this! Good idea to add beta python versions to CI setup, we should probably do that as well!

@erikogabrielsson
The error is caused by a missuse of Tifffile's interface from our side, where we accidently assumed that TiffPage.compression was a string and not an enum. So the code should change to using the public enum in tifffile instead to become robust:

from tifffile import COMPRESSION

...
if self.compression != COMPRESSION.JPEG:
    ...