Import keras requires Tensorflow 2.2 or higher

[AastaLLL]

Hi,

Just FYI.

We release a new TensorFlow package yesterday, which is v2.2.0.

$ sudo pip3 install --pre --extra-index-url https://developer.download.nvidia.com/compute/redist/jp/v44 tensorflow==2.2.0+nv20.6

Thanks.