Fix deprecated imports of scipy.ndimage.gaussian_filter

[rbu]

scipy deprecated the use of the ndimage.filters submodule in v1.8.0 and plans to remove the compatibility import in v2.0.0 The filters were availalble in the ndimage module going back at least to 2012, and I tested the import on scipy==1.1.0.

Fixes the following error:

$ python -W always -c "import albumentations.augmentations.transforms" albumentations/albumentations/augmentations/geometric/functional.py:7: DeprecationWarning: Please use `gaussian_filter` from the `scipy.ndimage` namespace, the `scipy.ndimage.filters` namespace is deprecated.
  from scipy.ndimage.filters import gaussian_filter

[Dipet]

I think that we also need to update the version requirements for libs for these changes https://github.com/albumentations-team/albumentations/blob/master/setup.py#L8

[rbu]

I think that we also need to update the version requirements for libs for these changes https://github.com/albumentations-team/albumentations/blob/master/setup.py#L8

Which dependency do you have in mind? Specifically for scipy, I tested that the "new" import location (i.e. the one that is not deprecated, and which this PR starts using) has been around in scipy 1.1.0 from 2012. I didn't run the full test suite to find out what the minimal version requirement actually are, but I doubt that this change would change that in practice.
That being said, I'm happy to run more tests or adapt version specs in this PR, if you let me know in what direction.

[jangop]

[...] Specifically for scipy, I tested that the "new" import location (i.e. the one that is not deprecated, and which this PR starts using) has been around in scipy 1.1.0 from 2012 [...]

In that case, specify scipy>=1.1.0 in setup.py. At the moment, no version is specified for scipy at all.

[rbu]

In that case, specify scipy>=1.1.0 in setup.py. At the moment, no version is specified for scipy at all.

I've adapted the branch accordingly and rebased to master.

[rbu]

Thank you for the timely review and merge @jangop @Dipet