[Docs] Add tags in README.md (#137)

* add tag in README.md

* fix linting issue

configs/lenet/README.md

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 ## Introduction
 
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 ```latex
 @ARTICLE{6795724,
   author={Y. {LeCun} and B. {Boser} and J. S. {Denker} and D. {Henderson} and R. E. {Howard} and W. {Hubbard} and L. D. {Jackel}},

configs/mobilenet_v2/README.md

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 ## Introduction
 
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 ```latex
 @INPROCEEDINGS{8578572,
   author={M. {Sandler} and A. {Howard} and M. {Zhu} and A. {Zhmoginov} and L. {Chen}},

configs/resnet/README.md

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 ## Introduction
 
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 ```latex
 @inproceedings{he2016deep,
   title={Deep residual learning for image recognition},

configs/resnext/README.md

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 ## Introduction
 
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 ```latex
 @inproceedings{xie2017aggregated,
   title={Aggregated residual transformations for deep neural networks},

configs/seresnet/README.md

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 ## Introduction
 
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 ```latex
 @inproceedings{hu2018squeeze,
   title={Squeeze-and-excitation networks},

configs/seresnext/README.md

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 ## Introduction
 
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 ```latex
 @inproceedings{hu2018squeeze,
   title={Squeeze-and-excitation networks},

configs/shufflenet_v1/README.md

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 ## Introduction
 
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 ```latex
 @inproceedings{zhang2018shufflenet,
   title={Shufflenet: An extremely efficient convolutional neural network for mobile devices},

configs/shufflenet_v2/README.md

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 ## Introduction
 
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 ```latex
 @inproceedings{ma2018shufflenet,
   title={Shufflenet v2: Practical guidelines for efficient cnn architecture design},

configs/vgg/README.md

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 ## Introduction
 
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 ```latex
 @article{simonyan2014very,
   title={Very deep convolutional networks for large-scale image recognition},