【开源实习】bert模型微调

[Alemax067]

任务链接：https://gitee.com/mindspore/community/issues/IAUP1T

结果：参考指标为在测试集上的准确率，mindspore + mindnlp 复现结果略优于 pytorch， 代码详细说明及结果见文件README.md

测试集准确率：

my results on mindspore

Model Variant	Accuracy on Dev Set
BERT (no finetuning)	81.25%
BERT (with finetuning)	90.07%

my results on pytorch

Model Variant	Accuracy on Dev Set
BERT (no finetuning)	81.03%
BERT (with finetuning)	89.84%

Original results from the repo

Model Variant	Accuracy on Dev Set
BERT (no finetuning)	82.59%
BERT (with finetuning)	88.29%