Allowing users to use the latest `tokenizers` release !
Author: Narsil
Pull request: yes

# What does this PR do?

- Allow users to use the most recent `tokenizers` version.
- Should be 100% backward compatible, but there were quite large changes to the actual codebase.

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Fixes # (issue)


## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
- [ ] Did you read the [contributor guideline](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md#start-contributing-pull-requests),
      Pull Request section?
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      [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.

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Models:

- albert, bert, xlm: @LysandreJik
- blenderbot, bart, marian, pegasus, encoderdecoder,  t5: @patrickvonplaten, @patil-suraj
- longformer, reformer, transfoxl, xlnet: @patrickvonplaten
- fsmt: @stas00
- funnel: @sgugger
- gpt2: @patrickvonplaten, @LysandreJik
- rag: @patrickvonplaten, @lhoestq
- tensorflow: @LysandreJik

Library:

- benchmarks: @patrickvonplaten
- deepspeed: @stas00
- ray/raytune: @richardliaw, @amogkam
- text generation: @patrickvonplaten
- tokenizers: @n1t0, @LysandreJik
- trainer: @sgugger
- pipelines: @LysandreJik

Documentation: @sgugger

HF projects:

- datasets: [different repo](https://github.com/huggingface/datasets)
- rust tokenizers: [different repo](https://github.com/huggingface/tokenizers)

Examples:

- maintained examples (not research project or legacy): @sgugger, @patil-suraj
- research_projects/bert-loses-patience: @JetRunner
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Comments:
You need to run `make style` when changing the setup.

_The documentation is not available anymore as the PR was closed or merged._

Failure seem unrelated. Yet rebasing on main to remove the failure linked to the Datasets release and re-laucnhing spurious tests would be helpful to ease everyone's mind :-)

@sgugger Should I wait for a second core maintainer's opinion on this ?

Nope, you can go ahead and merge :-) 

I couldn't immediately find the release process for this repository - when will this make it into a release? `tokenizers` (for versions earlier than 0.13.0) had no wheel available for Apple silicon, so I believe until this PR is released we're stuck with source builds for that dependency.

The next release of Transformers will be in a month roughly. In the meantime, you can install it from source.