Pig latin README may need to be updated

[shingtaklam1324]

The problem specification has updated on Feb 22. The overall message of the description is the same, but the wording has changed.

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[petertseng]

I request that the person who submits the PR to update the README please include https://github.com/exercism/problem-specifications/pull/1171 in the commit message, so that it is possible to tell from the logs where the change came from.