Cannot successfully convert convnext models to onnx using transformers.onnx
### System Info

transformers==4.20.1

onnxruntime==1.11.1

### Who can help?

_No response_

### Information

- [ ] The official example scripts
- [ ] My own modified scripts

### Tasks

- [ ] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [ ] My own task or dataset (give details below)

### Reproduction

`python -m transformers.onnx --model="facebook/convnext-base-224-22k" convnext-base-224-22k  `

Used the above command to convert. The conversion to onnx format is not successful. 

Error : 

```
2022-07-08 15:21:40.258366: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcudart.so.11.0'; dlerror: libcudart.so.11.0: cannot open shared object file: No such file or directory
2022-07-08 15:21:40.258414: I tensorflow/stream_executor/cuda/cudart_stub.cc:29] Ignore above cudart dlerror if you do not have a GPU set up on your machine.
2022-07-08 15:22:35.205167: I tensorflow/stream_executor/cuda/cuda_gpu_executor.cc:975] successful NUMA node read from SysFS had negative value (-1), but there must be at least one NUMA node, so returning NUMA node zero
2022-07-08 15:22:35.210358: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcudart.so.11.0'; dlerror: libcudart.so.11.0: cannot open shared object file: No such file or directory
2022-07-08 15:22:35.210594: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcublas.so.11'; dlerror: libcublas.so.11: cannot open shared object file: No such file or directory
2022-07-08 15:22:35.210711: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcublasLt.so.11'; dlerror: libcublasLt.so.11: cannot open shared object file: No such file or directory
2022-07-08 15:22:35.210841: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcufft.so.10'; dlerror: libcufft.so.10: cannot open shared object file: No such file or directory
2022-07-08 15:22:35.211142: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcurand.so.10'; dlerror: libcurand.so.10: cannot open shared object file: No such file or directory
2022-07-08 15:22:35.211293: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcusolver.so.11'; dlerror: libcusolver.so.11: cannot open shared object file: No such file or directory
2022-07-08 15:22:35.211417: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcusparse.so.11'; dlerror: libcusparse.so.11: cannot open shared object file: No such file or directory
2022-07-08 15:22:35.211569: W tensorflow/stream_executor/platform/default/dso_loader.cc:64] Could not load dynamic library 'libcudnn.so.8'; dlerror: libcudnn.so.8: cannot open shared object file: No such file or directory
2022-07-08 15:22:35.211603: W tensorflow/core/common_runtime/gpu/gpu_device.cc:1850] Cannot dlopen some GPU libraries. Please make sure the missing libraries mentioned above are installed properly if you would like to use GPU. Follow the guide at https://www.tensorflow.org/install/gpu for how to download and setup the required libraries for your platform.
Skipping registering GPU devices...
2022-07-08 15:22:35.247214: I tensorflow/core/platform/cpu_feature_guard.cc:193] This TensorFlow binary is optimized with oneAPI Deep Neural Network Library (oneDNN) to use the following CPU instructions in performance-critical operations:  AVX2 FMA
To enable them in other operations, rebuild TensorFlow with the appropriate compiler flags.
Some weights of the model checkpoint at facebook/convnext-base-224-22k were not used when initializing ConvNextModel: ['classifier.bias', 'classifier.weight']
- This IS expected if you are initializing ConvNextModel from the checkpoint of a model trained on another task or with another architecture (e.g. initializing a BertForSequenceClassification model from a BertForPreTraining model).
- This IS NOT expected if you are initializing ConvNextModel from the checkpoint of a model that you expect to be exactly identical (initializing a BertForSequenceClassification model from a BertForSequenceClassification model).
Using framework PyTorch: 1.11.0+cu102
Validating ONNX model...
	-[✓] ONNX model output names match reference model ({'last_hidden_state'})
	- Validating ONNX Model output "last_hidden_state":
		-[✓] (2, 1024, 7, 7) matches (2, 1024, 7, 7)
		-[x] values not close enough (atol: 1e-05)
Traceback (most recent call last):
  File "/usr/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/media/dingusagar/Data/python-envs/onnx-env/lib/python3.7/site-packages/transformers/onnx/__main__.py", line 107, in <module>
    main()
  File "/media/dingusagar/Data/python-envs/onnx-env/lib/python3.7/site-packages/transformers/onnx/__main__.py", line 100, in main
    validate_model_outputs(onnx_config, preprocessor, model, args.output, onnx_outputs, args.atol)
  File "/media/dingusagar/Data/python-envs/onnx-env/lib/python3.7/site-packages/transformers/onnx/convert.py", line 441, in validate_model_outputs
    "Outputs values doesn't match between reference model and ONNX exported model: "
ValueError: Outputs values doesn't match between reference model and ONNX exported model: Got max absolute difference of: 0.000457763671875

```



### Expected behavior

Expected the validation step to be successful.
You need to provide the `--feature` argument<|||||>@NielsRogge is right, if you want to perform image classification you need to provide the `--feature image-classification` argument.

Besides, it is also possible that the default absolute tolerance used for validating the model is not adapted to different sizes/checkpoints of the same architecture. We use `"facebook/convnext-tiny-224"` in our internal tests, but, according to the error you got, `"facebook/convnext-base-224-22k"` may require the additional argument `--atol 1e-03`, which is still acceptable.<|||||>Thanks for the reply @NielsRogge @regisss . 

`--atol 1e-03` fixed the issue. 