Fix PyTorch index url for package (#286)

The default PyTorch 2.8.0 package uses CUDA 12.8. We need to specify the
PyTorch CUDA 12.9 index URL in order to pick up the right version.

This also switches the dev dockerfile to CUDA 12.9 in order to match the
package.

---------

Signed-off-by: Matthew Cong <mcong@nvidia.com>

Author: matthewdcong

Dockerfile

@@ -1,4 +1,4 @@
-FROM nvidia/cuda:12.8.1-cudnn-devel-ubuntu22.04
+FROM nvidia/cuda:12.9.1-cudnn-devel-ubuntu22.04
 
 # Set environment variables to prevent interactive prompts during installation.
 ENV DEBIAN_FRONTEND=noninteractive

README.md

@@ -48,7 +48,7 @@ are provided.
 Install fvdb_core using the following pip command.
 
 ```
-pip install fvdb_core==0.3.0+pt28.cu129 --extra-index-url="https://d36m13axqqhiit.cloudfront.net/simple" torch==2.8.0
+pip install fvdb_core==0.3.0+pt28.cu129 --extra-index-url="https://d36m13axqqhiit.cloudfront.net/simple" torch==2.8.0 --extra-index-url https://download.pytorch.org/whl/cu129
 ```
 
 ## Building *f*VDB from Source