Python version restricted to >=3.9, inability to use official docker containers of tensorflow

[xehartnort]

Since the addition of dp-accounting, the minimum version of python required to use the latest releases of this package is restricted to >=3.9. This restriction causes plenty of inconsistencies when using the official docker images for tensorflow and the official nvidia tensorflow images, given that they only support python3.8.

To sum up, it is not possible to use the latest version of tensorflow-privacy with the official docker containers of tensorflow due to the python version required.

Consequently, it will be nice to add a note in the README indicating that the python version required is >=3.9.

[minwoo33park]

This could be a workaround.
https://cloud.google.com/tensorflow-enterprise/docs/overview
https://pantheon.corp.google.com/gcr/images/deeplearning-platform-release