short name for focal package in ppa

[brainchild0]

Following #321, the PPA currently supports the package name bookworm, as well as the fully-qualified name based on the Github domain name, for Ubuntu versions up to and including Bionic, but only the latter for more recent versions. Would users of the more recent versions be required to use the long-form name, or might the repository be populated with packages using the short package name for these Ubuntu versions?