I tried it on Ubuntu 20.04 LTS which is also focal, but I'm getting this error on "apt update": Get:4 https://repo.waydro.id focal InRelease [1,343 B]

I tried it on Ubuntu 20.04 LTS which is also focal, but I'm getting this error on "apt update": Get:4 https://repo.waydro.id focal InRelease [1,343 B] Err:4 https://repo.waydro.id focal InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 959FE34E90E51522 Reading package lists... Done W: GPG error: https://repo.waydro.id focal InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 959FE34E90E51522 E: The repository 'https://repo.waydro.id focal InRelease' is not signed. Is that an issue with the waydroid repository, or with my setup?