i see 2 errors something with apt key for microsoft repo. Maybe this will
Note not tested from me.
# uninstall code
sudo apt remove code
sudo rm /etc/apt/sources.list.d/vscode.list
sudo apt update # should succeed now
# download code and reinstall it
wget -O ~/Downloads/code.deb https://update.code.visualstudio.com
Packages in a repository can be cryptographically signed. That's to ensure that the packages have not been tampered with. If they had been tampered with, the signature wouldn't be correct anymore.
To check the signature, your system needs the public key of the repository in question. Those keys have kind of a "shelf life", meaning they expire after ...