Fix year in noisy channel citation (#842)
Fix year in noisy channel citation (#842)

Summary:
2018->2019
Pull Request resolved: https://github.com/fairinternal/fairseq-py/pull/842

Differential Revision: D16973530

Pulled By: nng555

fbshipit-source-id: 00207b79821ac0257a53a0581a84582130e1bff5

pytorch/fairseq,pytorch/fairseq,pytorch/fairseq