Update Seq2Seq QA example script to use SQuAD metric.
Author: karthikrangasai
Pull request: yes

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Comments:
In the extractive method, the logits are used to score the outputs but for generative there isn't any value we can define to rank it because the sentence is already generated. So I suppose we can just use one feature per example.

It looks like GitHub does not like your rebase and is showing a diff with ~200 files touched. Could you close this PR and create a fresh one?

Sorry for the late reply.
I didn't notice the error while pushing the code.
I have created the new PR here at #14335 .
I will close this one now.