What-If Tool 1.6 release - Code now fully moved out of TensorBoard repository

[jwe...@google.com]

The What-If Tool version 1.6.0 has been released, as new versions of all available pip packages (witwidget, witwidget-gpu, and tensorboard-plugin-wit), and the release notes have been updated.

The main change is that there is no longer any WIT-related code in the TensorBoard repository. Users of WIT in TensorBoard will see no change in how they use the tool, but it is now implemented as a dynamic plugin, through the new tensorboard-plugin-wit pip package. The next release of TensorBoard (to be released in tandem with TensorFlow 2.2.0) will be the first to include WIT as a dynamic plugin, as opposed to a plugin built into the TensorBoard code-base.

The development instructions have been updated to explain how to test local WIT changes in your local TensorBoard, if you are editing WIT code and want to see the result of the change inside of WIT in TensorBoard.

Please reach out with any questions. Thanks!

-James