Update python-publish.yml to Python 3.7 (awslabs#949)

Avoid circular import: move cleanup method to training.py (awslabs#932)

fix warmup of learning rate so that it works properly w/ continued tr… (

awslabs#926)

Co-authored-by: Steven Bradtke sjbradt <[email protected]>

Add some Sockeye publications (awslabs#912)

Make source/target data required for scoring. (awslabs#904)

Interleaved Multi-head Attention Operators (awslabs#884)

Replaced batched dot product in multi-head attention with interleaved_matmul attention operators to improve performance. Also changes the batch-major data to time-major format while in the model to comply with the new operator requirements.

Add ability to cache encoder outputs of model (awslabs#858)

Add SSRU layer and decoder (awslabs#851)

- Adds layers.SSRU, which implements a Simpler Simple Recurrent Unit as described by Kim et al, 2019.
- Adds ssru_transformer option to --decoder, which enables the usage of SSRUs as a replacement for the decoder-side self-attention layers.
- Reduces the number of arguments for MultiHeadSelfAttention.hybrid_forward().
previous_keys and previous_values should now be input together as previous_states, a list containing two symbols.

Fix batch sizing errors introduced in c00da52 (awslabs#849)

Option to suppress console output for secondary workers (awslabs#841)