Add tpu_zone and gcp_project in training_args_tf.py
# What does this PR do?
Add ```tpu_zone``` and ```gcp_project``` in ```training_args_tf.py```.
For using TPUs created in a zone different from the VM zone, ```tpu_zone``` must be allocated.

See official Bert repo,
https://github.com/google-research/bert/blob/eedf5716ce1268e56f0a50264a88cafad334ac61/run_pretraining.py#L426

- trainer: @sgugger 
@sgugger 
I got the error message with ```make style```.

```
kiyoung@medical-ubuntu:~/transformers$ make style
running deps_table_update
updating src/transformers/dependency_versions_table.py
black examples tests src utils
make: black: Command not found
Makefile:42: recipe for target 'style' failed
make: *** [style] Error 127
```<|||||>You need to follow the steps of the [contributing guide](https://github.com/huggingface/transformers/blob/master/CONTRIBUTING.md) do be able to make PRs. In particular you didn't follow the installation part by running `pip install -e ".[dev]"` since you don't have `black` installed.<|||||>@sgugger 
Thanks, I did it.<|||||>Thanks for fixing! Now the problem comes from a new release of jax, which has been fixed in master so this is safe to merge.<|||||>This PR introduced a `datasets` submodule. I'm removing it in #9868.