Update graph_nets_basic example to TF2

[Mistobaan]

see #115

[alvarosg]

Thanks for the PR @Mistobaan !

It seems like the outputs of the notebook look reasonable! To make the review easier, do you think it would be possible to:

• Empty the notebook outputs (we prefer not committing binary data, and the demos are super easy to run in Google Colaboratory anyway).
• Is the first commit a pristine copy? Ideally, the first commit would be a verbatim forked version of the tf1 version and the second commit should show a relatively clean diff for reviewing purposes, do you think that you can split/squash the commits into that?

Thanks in advance :)

[Mistobaan]

@alvarosg I agree with your points. re-created the commits and pushed.

[alvarosg]

Just to update on my end:

Thanks for the latest changes @Mistobaan , I will review it all at once the small TF2 specific example of usage with tf.function is provided, please let me know if plans change :)

[zafarali]

Hi @Mistobaan, I was wondering if you were planning to add the tf.function example. Let me know!

[alvarosg]

Thanks for the contribution!

I am merging this for now. Please, let me know if you are interested on adding the tf.function example on a separate PR.

Thanks again!