update "Using cuBLAS" to use correct update cuda compile flag (#876)

It seems like the previous `-DGGML_CUBLAS=ON` compile flag was deprecated.

diff --git a/README.md b/README.md
index e85f2a9299804cc720c6073a9d463ead6388349d..af7ac97c53b7c5581872f2eb09e49b5b1951cac0 100644 (file)
--- a/README.md
+++ b/README.md
@@ -105,7 +105,7 @@ cmake -DGGML_METAL=ON -DBUILD_SHARED_LIBS=Off ..
 
 ```bash
 # fix the path to point to your CUDA compiler
-cmake -DGGML_CUBLAS=ON -DCMAKE_CUDA_COMPILER=/usr/local/cuda-12.1/bin/nvcc ..
+cmake -DGGML_CUDA=ON -DCMAKE_CUDA_COMPILER=/usr/local/cuda-12.1/bin/nvcc ..
 ```
 
 ## Using hipBLAS