Adding Igbo monolingual dataset
CONTRIBUTOR
@lhoestq Thank you for the review. I have made all the changes you mentioned. PTAL! 
2020-12-20T23:45:48Z
https://github.com/huggingface/datasets/pull/1535#issuecomment-748689285
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2020-12-20T23:45:48Z
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This PR adds the Igbo Monolingual dataset.
Data: https://github.com/IgnatiusEzeani/IGBONLP/tree/master/ig_monoling
Paper: https://arxiv.org/abs/2004.00648  