update jtvae readme

Author: liugangcode

README.md

@@ -175,6 +175,7 @@ predictions = model.predict(smiles_list)
 | DiGress    | [DiGress: Discrete Denoising Diffusion for Graph Generation. ICLR 2023](https://openreview.net/forum?id=UaAD-Nu86WX) |
 | GDSS       | [Score-based Generative Modeling of Graphs via the System of Stochastic Differential Equations. ICML 2022](https://proceedings.mlr.press/v162/jo22a/jo22a.pdf) |
 | MolGPT     | [MolGPT: Molecular Generation Using a Transformer-Decoder Model. Journal of Chemical Information and Modeling 2021](https://pubs.acs.org/doi/10.1021/acs.jcim.1c00600) |
+| JTVAE     | [Junction Tree Variational Autoencoder for Molecular Graph Generation. ICML 2018.](https://proceedings.mlr.press/v80/jin18a) |
 | GraphGA    | [A Graph-Based Genetic Algorithm and Its Application to the Multiobjective Evolution of Median Molecules. Journal of Chemical Information and Computer Sciences 2004](https://pubs.acs.org/doi/10.1021/ci034290p) |
 | LSTM (SMILES)        | [Long short-term memory (Neural Computation 1997)](https://ieeexplore.ieee.org/abstract/document/6795963) based on SMILES strings |