updates Keras and tensorflow version [MNT]

[solegalli]

At the moment, there are 4 tests that are failing in test_keras.py. But more important than that, Keras has migrated its backend functionality.

Currently, we do import keras.backend as K and from K we use functions like argmax, gradient and so on. Those functions don't live there any more. I think, we may find them in tensforflow.keras.backend, but I am not absolutely sure. Anyhow, if we swap keras.backend for tensorflow.keras.backend, then we get other errors, like keras can't accept a tensorflow tensor.

I am not an avid Keras/tensorflow user, so I am a bit lost here. Any help/pointers will be welcome!

Anyhow, i think we need to update the files explain_prediction.py and grandcam.py inside the keras folder inside eli5.

FYI @lopuhin @kmike

[lopuhin]

@solegalli I think with current state of Keras 3, it seems better to target using keras instead of tensorflow.keras, even if we still will only support/test tensorflow backend of keras. Some operations like argmax are present in keras.ops: https://keras.io/api/ops/numpy/#argmax-function but porting the rest of the code could be non-trivial.

[lopuhin]

See also #31 which seems to add support for more recent TF versions

[lopuhin]

Thanks for starting this @solegalli , let me close this one as now we support modern Keras via #58