fix expired link in python onnxruntime readme (#1013)

Meng Wei

2023-10-17 8a16e1c13e91c9a7c43ba546fd71b85765d9469f

1
{"unk_token": "<|endoftext|>", "bos_token": "<|endoftext|>", "eos_token": "<|endoftext|>", "add_prefix_space": false, "model_max_length": 1024, "special_tokens_map_file": null, "name_or_path": "gpt2", "tokenizer_class": "GPT2Tokenizer"}