[Building/Packaging] Provide AppStream metainfo

[letsfindaway]

For software catalogs (like KDE Discover) it is essential that a metainfo file is provided by the package. This may include a short description and screenshots.

@jbruechert already provides such files with the Flatpak build at https://github.com/flathub/ch.openboard.OpenBoard. So I would like to ask whether we can re-use these files.

I would at least like to include them into my openSUSE builds. But it would even be better if they can also be part of the upstream project. However then they also have to be maintained there.

[jbruechert]

You can absolutely use my appstream metainfo file if you want. If it is maintained upstream that also helps me a lot with the flatpak.

[letsfindaway]

You can absolutely use my appstream metainfo file if you want. If it is maintained upstream that also helps me a lot with the flatpak.

Thank you very much! One question: What is the purpose of keeping the older releases in the appdata.xml? At least in the repositories of openSUSE Leap most older package versions are no longer available, only the one which was initially released with a distro version and the latest update. So wouldn't it be sufficient to only list the latest release?

[jbruechert]

For OpenBoard only keeping the latest release is probably okay. In KDE we also generate a website with changelogs between all releases from it, so I'm probably just used to keeping them.

[letsfindaway]

The chance of missing the update of the metainfo when a new version is released is very high. so I think about automating this.

• Provide a ch.openboard.OpenBoard.metainfo.xml.in template file in the repository.
• This template contains just one description for the latest version, which is pointing to the release in GitHub.
• The version number and release dates are provided as template variables.
• Use CMake configure_file to replace the variables with the actual values from version.txt.