Update n-series-driver-setup.md

The public key for the NVIDIA Cuda repository was changed on April 27. Details can be found in this article:
https://forums.developer.nvidia.com/t/notice-cuda-linux-repository-key-rotation/212771

Author: Bijuth-HPC

articles/virtual-machines/linux/n-series-driver-setup.md

@@ -55,7 +55,7 @@ Then run installation commands specific for your distribution.
    wget -O /tmp/${CUDA_REPO_PKG} https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/${CUDA_REPO_PKG} 
 
    sudo dpkg -i /tmp/${CUDA_REPO_PKG}
-   sudo apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/7fa2af80.pub 
+   sudo apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1604/x86_64/3bf863cc.pub
    rm -f /tmp/${CUDA_REPO_PKG}
 
    sudo apt-get update