Fully remove the use of the rasterio `affine` property

[perrygeo]

The src.affine property of Rasterio datasets is deprecated.

We do the right thing in rasterstats.io

python-rasterstats/src/rasterstats/io.py

Line 242 in a0eef4e

self.affine = guard_transform(self.src.transform)

But elsewhere, in main and in the tests, we access the affine property directly.

Also we use the affine argument name everywhere - this should be changed (in a backwards compatible way) to transform

[gfairchild]

I've got a related question. If I pass in src.transform to the affine argument in zonal_stats, will things break? I haven't tried this yet, but I'm curious. Just looking ahead to rasterio 1.0.

[gfairchild]

I just answered my own question: the answer is no, things don't break. I just switched to rasterio 1.0a9, and passing src.transform to affine appears to be working perfectly.

[perrygeo]

We've moved over to using transform everywhere when talking to Rasterio dataset objects.

We're still using the affine parameter name for e.g. the keyword argument to zonal_stats. Not a high priority to change it. Closing here for now.