 Unrecognized configuration class <class 'transformers.configuration_electra.ElectraConfig'>
# 🐛 Bug

## Information

Model I am using : ahotrod/electra_large_discriminator_squad2_512

This problem happened again, when I use ELECTRA on question-answering pipeline. My Transformers version is 2.11.0.

Code:
> from transformers import pipeline, AutoTokenizer, AutoModelForQuestionAnswering
> 
> tokenizer = AutoTokenizer.from_pretrained("ahotrod/electra_large_discriminator_squad2_512")
> model = AutoModelForQuestionAnswering.from_pretrained("ahotrod/electra_large_discriminator_squad2_512")

Error:

> Traceback (most recent call last):
>   File "albert_qa.py", line 5, in <module>
>     model = AutoModelForQuestionAnswering.from_pretrained("ahotrod/electra_large_discriminator_squad2_512")
>   File "/home/aim/ANDY-project/sentence-transformers-env/lib/python3.6/site-packages/transformers/modeling_auto.py", line 1004, in from_pretrained
>     ", ".join(c.__name__ for c in MODEL_FOR_QUESTION_ANSWERING_MAPPING.keys()),
> ValueError: Unrecognized configuration class <class 'transformers.configuration_electra.ElectraConfig'> for this kind of AutoModel: AutoModelForQuestionAnswering.


- `transformers` version: 2.11.0
- Platform: Ubuntu
- Python version: 3.6.9
- PyTorch version (GPU?): 1.5.1

Hi! Even though the ELECTRA model was added in version v2.8.0, the `ElectraForQuestionAnswering` head was only added in v3.0.0. You would need to upgrade your `transformers` version to at at least v3.0.0 for your code to work!<|||||>I am trying to use pretrained Distilbert in EncoderDecoderModel but i am getting this error. How can i leverage pretrained distilbert in EncoderDecoderModel.

`ValueError: Unrecognized configuration class <class 'transformers.configuration_distilbert.DistilBertConfig'> for this kind of AutoModel: AutoModelForCausalLM.
Model type should be one of CamembertConfig, XLMRobertaConfig, RobertaConfig, BertConfig, OpenAIGPTConfig, GPT2Config, TransfoXLConfig, XLNetConfig, XLMConfig, CTRLConfig, ReformerConfig, BertGenerationConfig.`