[Don't merge] Run make style on templates
When run `make style` locally, these files got modified. 

I noticed that `black` and `isort` seem to have conflicts on these files. Is there a solution?

```
> make style
black --line-length 119 --target-version py35 examples templates tests src utils
reformatted /Users/canwenxu/transformers/src/transformers/__init__.py
reformatted /Users/canwenxu/transformers/templates/adding_a_new_example_script/run_xxx.py
reformatted /Users/canwenxu/transformers/templates/adding_a_new_example_script/utils_xxx.py
All done! ✨ 🍰 ✨
3 files reformatted, 339 files left unchanged.
isort --recursive examples templates tests src utils
Fixing /Users/canwenxu/transformers/templates/adding_a_new_example_script/run_xxx.py
Fixing /Users/canwenxu/transformers/templates/adding_a_new_example_script/utils_xxx.py
Fixing /Users/canwenxu/transformers/src/transformers/__init__.py
```
It seems to be an isort version problem