docs: update roadmap

Author: dmitryusenko

README.md

@@ -214,7 +214,7 @@ const ownsTheCar = await classifier.predict([0.2, 0.76, 0]);
 ## Roadmap
 
 - [x] Binary classification ([#1](https://github.com/RonasIT/tfjs-node-helpers/pull/1))
-- [ ] Asynchronously loaded datasets ([#14](https://github.com/RonasIT/tfjs-node-helpers/issues/14))
+- [x] Asynchronously loaded datasets ([#14](https://github.com/RonasIT/tfjs-node-helpers/issues/14))
 - [ ] Add an example of queued feature extraction and evaluation ([#12](https://github.com/RonasIT/tfjs-node-helpers/issues/12))
 - [ ] Add an example of storing the extracted features ([#13](https://github.com/RonasIT/tfjs-node-helpers/issues/13))
 - [ ] Feature normalization ([#5](https://github.com/RonasIT/tfjs-node-helpers/issues/5))