OpenNMT-tf 2.25.0

New features

• Support TensorFlow 2.8
• Add training flag --continue_from_checkpoint to simplify continuing the training in another model directory (to be used in combination with --checkpoint_path)

Fixes and improvements

• Fix target unknowns replacement when the source has BOS or EOS tokens
• Update length constraints in Transformer automatic configuration to work with multiple sources
• Allow explicit configuration of the first argument of learning rate schedules (if not set, learning_rate is passed as the first argument)