为了安装 pytorch，我安装了 CUDA、cuDNN 等。安装 pytorch 后，我这样做sudo apt update，然后出现这样的错误，
Get:2 file:/var/cudnn-local-repo-ubuntu2004-8.9.1.23 InRelease
Ign:2 file:/var/cudnn-local-repo-ubuntu2004-8.9.1.23 InRelease
Get:3 file:/var/cudnn-local-repo-ubuntu2004-8.9.1.23 Release
Err:3 file:/var/cudnn-local-repo-ubuntu2004-8.9.1.23 Release
File not found - /var/cudnn-local-repo-ubuntu2004-8.9.1.23/Release (2: No such file or directory)
Get:1 file:/var/cuda-repo-ubuntu2004-11-8-local InRelease [1,575 B]
Hit:4 https://nvidia.github.io/libnvidia-container/stable/ubuntu18.04/amd64 InRelease
Hit:5 https://dl.google.com/linux/chrome/deb stable InRelease
Hit:6 http://security.ubuntu.com/ubuntu focal-security InRelease
Hit:7 http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu focal InRelease
Hit:8 http://kr.archive.ubuntu.com/ubuntu focal InRelease
Hit:9 http://kr.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:10 http://ppa.launchpad.net/micahflee/ppa/ubuntu focal InRelease
Get:11 http://kr.archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Reading package lists... Done
E: The repository 'file:/var/cudnn-local-repo-ubuntu2004-8.9.1.23 Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
我该如何修复它？