Chao Pang

Results 3 issues of Chao Pang

- Upload Tensorflow to 2.12 so we can use TensorFlow's version of MultiHeadAttention - Replace our own implementation of [MultiHeadAttention](https://github.com/cumc-dbmi/cehr-bert/blob/8862fd6a1f026839d301625fb30a1ba7e19a4672/models/custom_layers.py#L81) with the Tensorflow version of [MultiHeadAttention](https://www.tensorflow.org/api_docs/python/tf/keras/layers/MultiHeadAttention) - Toggle `mask` at...