Unable to install from https://alltomp3.org/ instructions on Ubuntu 23.04

[tomchiverton]

The script piped to bash ran fine till the end:

Detected operating system as Ubuntu/lunar.
Checking for curl...
Detected curl...
Checking for gpg...
Detected gpg...
Detected apt version as 2.6.0
Running apt-get update... done.
Installing apt-transport-https... done.
Installing /etc/apt/sources.list.d/AllToMP3_alltomp3.list...done.
Importing packagecloud gpg key... Packagecloud gpg key imported to /etc/apt/keyrings/AllToMP3_alltomp3-archive-keyring.gpg
done.
Running apt-get update... done.

The repository is setup! You can now install packages.
falken@wopr:/tmp$ sudo apt install alltomp3
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
E: Unable to locate package alltomp3

running apt update manually provides more details :

E: The repository 'https://packagecloud.io/AllToMP3/alltomp3/ubuntu lunar Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.