v5.5.0

[HolyWu]

• Add 4.25.heavy and 4.26.heavy models.
• Add auto_download parameter to allow only download the specified model at first run rather than forcibly download all models at once.
• Usage of reducing frame rate is specifically rejected now.
• Remove pre-allocated timestep tensors to avoid potential OOM due to large factor_num.

---

This discussion was created from the release v5.5.0.