Hello and Welcome to the community,
Please try this, it is working just the version have changed.
Also the certificate is expired and I will update the khadas team to update the certificate.
Also no certificate
Err:9 https://dl.khadas.com/repos/vim3 bionic Release
Certificate verification failed: The certificate is NOT trusted. The certificate chain uses expired certificate. Could not handshake: Error in the certificate verification. [IP: 184.108.40.206 443]
Reading package lists… Done
E: The repository ‘https://dl.khadas.com/repos/vim3 bionic 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.
Please try his advice.