Update setup.py to be compatible with pipenv
# What does this PR do?
This enables installing transformers from source using pipenv.
Currently installing transformers through pipenv via a git source is blocked by this issue:  https://github.com/pypa/pipenv/issues/5167#issuecomment-1349316531

Installation will fail with:
```
AttributeError: 'Subscript' object has no attribute 's'
```
## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
- [x] Did you read the [contributor guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      Pull Request section?
- [ ] Was this discussed/approved via a Github issue or the [forum](https://discuss.huggingface.co/)? Please add a link
      to it if that's the case.
- [ ] Did you make sure to update the documentation with your changes? Here are the
      [documentation guidelines](https://github.com/huggingface/transformers/tree/main/docs), and
      [here are tips on formatting docstrings](https://github.com/huggingface/transformers/tree/main/docs#writing-source-documentation).
- [ ] Did you write any new necessary tests?


## Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

@sgugger 
> I'm confused. `install_requires` is already a list as seen on line 415.

Thanks for taking a look @sgugger!

It seems to be a requirementslib bug that occurs when one of the items in the list of dependencies is declared with a string interpolation..

I'm not sure why using the list constructor fixes the bug. This is the behavior when installing transformers through pipenv without the bugfix:

```
$ pipenv install git+https://github.com/huggingface/transformers#egg=transformers
Installing git+https://github.com/huggingface/transformers@v4.30.0#egg=transformers...
Resolving
git+https://github.com/huggingface/transformers@v4.30.0#egg=transformers...
✘ Locking Failed!
Traceback (most recent call last):
  ...
  File "/home/gmathews/.local/lib/python3.8/site-packages/pipenv/vendor/requirementslib/models/setup_info.py", line 659, in _find_install_requires
    return [el.s for el in variable.elts]
  File "/home/gmathews/.local/lib/python3.8/site-packages/pipenv/vendor/requirementslib/models/setup_info.py", line 659, in <listcomp>
    return [el.s for el in variable.elts]
AttributeError: 'Subscript' object has no attribute 's'
```<|||||>The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/transformers/pr_24789). All of your documentation changes will be reflected on that endpoint.