Add testing against CUDA 12.9

Author: NicolasHug

.github/workflows/linux_cuda_wheel.yaml

@@ -67,7 +67,9 @@ jobs:
           # For the actual release we should add that label and change this to
           # include more python versions.
         python-version: ['3.9']
-        cuda-version: ['12.6', '12.8']
+        # We test against 12.6 and 12.9 to avoid having too big of a CI matrix,
+        # but for releases we should add 12.8.
+        cuda-version: ['12.6', '12.9']
         # TODO: put back ffmpeg 5 https://github.com/pytorch/torchcodec/issues/325
         ffmpeg-version-for-tests: ['4.4.2', '6', '7']