Tensor Flow 2 Compatibility

[RAFALAMAO]

I added some changes for run "python3 runGan.py 1" with Tensorflow 2.

Also you need to install:
pip install tf_slim
pip install tensorflow_addons

[Entretoize]

These changes allowes me to run the code with python 3.8 and tensorflow 2

[kalomano]

Nice work, it works for me! Thanks!
I think this solution uses a deprecated method, be careful.

[nathandtrone]

I'm working on a Google Colab with these changes in mind. I'll report back with the results if I don't forget, but cursory glance and one test shows it is a functional solution. I recommend merging as the updated tensor flow progresses.

[s-tweed]

Thank you for this, it is very helpful and should probably be merged to master! I spent about an hour trying to do this myself before realizing someone had probably already done it...