Broken link in README.md, section "BioBERT for Named Entity Recognition"

[kgene521]

Attention: @minstar
https://github.com/minstar

The link in the first paragraph of README.md is broken:

"To train an NER model with BioBERT-v1.1 (base), run the command below. Before training, please run ./preprocess.sh to preprocess the datasets downloaded in biobert-pytorch (see here)."