asgen-config-generator doesn't include unreleased alpine versions where binary packages are already available
As of writing, Alpine 3.19 is in rc3 state. Binary packages are available, but the version is not released yet.
The asgen-config-generator uses https://alpinelinux.org/releases.json to determine which releases to build appstream data for, and so there currently is no appstream data for 3.19.
This isn't ideal for testing 3.19, alpine-appstream-downloader gets a 404 error when trying to fetch the appstream data files. I wrote a patch to make it try edge in that situation (https://gitlab.com/pabloyoyoista/alpine-appstream-downloader/-/merge_requests/2), but it will still hit the 404 once per run.
Maybe a releases_wip.json or something could be added, that includes the unreleased versions? Not sure what the best path to implement this would be, or if getting the 404 from everybody running alpine-appstream-downloader once is a problem at all. Documenting this for future reference.