The citation in README should contain an author field

The current README suggests to cite NeMo RL as:

```
@misc{nemo-rl,
title = {NeMo RL: A Scalable and Efficient Post-Training Library},
howpublished = {\url{https://github.com/NVIDIA-NeMo/RL}},
year = {2025},
note = {GitHub repository},
}
```

but it has no author field. This makes it impractical to cite in scientific publications.