Add support for tf2 encoder_decoder
# 🌟 New model addition

I would like to add `TensorFlow-2` support for `encoder_decoder` model. I will soon create a PR, if this is approved.
Shall I start working on it if no one else is doing it?<|||||>Feel free to give it a try and tag me if you encounter any issues along the way! Just to set expectations, such a PR will be a longer project (~1 month) and is a relatively low priority for the library at the moment, so I might not be able to reply daily. 

But nevertheless, I'm more than happy to guide you through a PR :-) <|||||>Thanks! I will start the PR soon :)