add GPT-J ONNX config to Transformers (#16274)
* add GPT-J ONNX config to Transformers
* remove token-classification features mapping
Co-authored-by: lewtun <lewis.c.tunstall@gmail.com>
* add question-answering features mapping
Co-authored-by: lewtun <lewis.c.tunstall@gmail.com>
* add GPT2 config init to GPT2 config + copie shebang for fix-copies
Co-authored-by: ChainYo <t.chaigneau.tc@gmail.com>
Co-authored-by: lewtun <lewis.c.tunstall@gmail.com>
