Make readme benchmarks robust to CUDA not being present (#409)

Author: scotts

benchmarks/decoders/generate_readme_data.py

@@ -61,7 +61,8 @@ def main() -> None:
 
     decoder_dict = {}
     decoder_dict["torchcodec"] = TorchCodecPublic()
-    decoder_dict["torchcodec[cuda]"] = TorchCodecPublic(device="cuda")
+    if torch.cuda.is_available():
+        decoder_dict["torchcodec[cuda]"] = TorchCodecPublic(device="cuda")
     decoder_dict["torchvision[video_reader]"] = TorchVision("video_reader")
     decoder_dict["torchaudio"] = TorchAudioDecoder()
 
@@ -80,7 +81,7 @@ def main() -> None:
             batch_parameters=BatchParameters(batch_size=50, num_threads=10),
             resize_height=256,
             resize_width=256,
-            resize_device="cuda",
+            resize_device="cuda" if torch.cuda.is_available() else "cpu",
         ),
     )
     data_for_writing = {