SummarizationPipeline: init required task name (#5086)
SummarizationPipeline: init required task name (#5086)

* SummarizationPipeline: init required task name

* Update src/transformers/pipelines.py

Co-authored-by: Sam Shleifer <3738106568efe2af774328bb7c694b0424580931@gmail.com>

* Apply suggestions from code review

Co-authored-by: Sam Shleifer <3738106568efe2af774328bb7c694b0424580931@gmail.com>
huggingface/transformers,huggingface/transformers,huggingface/pytorch-transformers,huggingface/transformers,huggingface/transformers