Improve documentation when exporting a recipe

[pacospace]

What is the URL, file, or UI containing proposed doc change
Where does one find the original content or where would this change go?

This change would go in the main README of sparsify repository.

What is the current content or situation in question
https://github.com/neuralmagic/sparsify#exporting-a-recipe

What is the proposed change
In the main README it should be mentioned that tensorflow or torch should be installed with sparsify to be able to export them.

Moreover it should be mentioned the range of version for torch or tensorflow that can be handled:

Additional context
Related-To new tutorial with NerualMagic: AICoE/elyra-aidevsecops-tutorial#297

[markurtz]

Thanks for this suggestion @pacospace, we will get this updated!

[markurtz]

Closing this out now as we added in a note in the README. We'll work towards easier flows with this as well through optional pathways in pip installs.