While running sudo apt update
the following Warning, followed by an Error raises:
W: GPG error: http://packages.cloud.google.com/apt cloud-sdk InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B53DC80D13EDEF05
E: The repository 'http://packages.cloud.google.com/apt cloud-sdk InRelease' is not signed.
Does anybody know how can I solve it?