Make Conv1D.bias optional
# What does this PR do?

A simple change to make Conv1D.bias optional.

## Before submitting
- [ ] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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      Pull Request section?
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      to it if that's the case.
- [x] Did you make sure to update the documentation with your changes? Here are the
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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.

Conv1D is used in GPT models: @patrickvonplaten, @LysandreJik

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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
- research_projects/distillation: @VictorSanh

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_The documentation is not available anymore as the PR was closed or merged._<|||||>@sgugger thanks for the comment. Then in the case that if I'd like to disable bias in GPT-2 models, should we directly change the GPT-2 model implementation to avoid custom Conv1D, and deprecate it?<|||||>You can change the modeling code as you'd like to suit your need. We won't upstream it since it's not in the official GPT-2 code though.<|||||>So the code change guides are summarized as follows:
1. Official model code (e.g., GPT-2) cannot be changed to deprecate the use of Conv1D.
2. Conv1D in transformers is legacy and only used in some existing models (e.g., GPT-2).

IIUC, then I still feel this PR is required, as Conv1D cannot be deprecated and is still a "building block" of some models. Is there any strong restriction (e.g., code freeze) that these legacy code cannot be changed?

Thanks.<|||||>You can open a PR to remove the Conv1D use in GPT-2 and, but we won't add a new argument to control the bias like this. You can copy the modeling code and adapt it to your needs if this is something you want yourself.<|||||>I see. Yeah that makes sense and is actually my intention. I don't plan to add an argument to existing GPT-2. I just want to make sure I don't need to change other places in transformers to disable the bias in GPT-2. Thanks.