Fix deprecated top-level developer_name in AppData XML

[musicinmybrain]

Use the name element in a developer block instead, as recommended by appstreamcli 1.0.0.

This fixes all warnings when validating the AppData XML file, although there are still informational messages:

I: org.pencil2d.Pencil2D:6: developer-id-missing
   The `developer` element is missing an `id` property, containing a unique string ID for the
   developer. Consider adding a unique ID.

✔ Validation was successful: infos: 1, pedantic: 2

[musicinmybrain]

Let me clarify that appstream 1.0.0 has not yet been released, and my appstream is a pre-release as currently packaged in Fedora Linux Rawhide (the development version of the OS), corresponding to ximion/appstream@d88ed03. See also ximion/appstream#244.

[J5lx]

Thanks for the PR. I see you also removed the previous developer_name tag, but won’t this degrade compatibility with current versions, considering that 1.0 has not been released yet? Would it be fine to keep developer_name for now (alongside the new tag) until more distributions have updated to 1.0?

On a completely unrelated note, the other day I saw a review (from ODRS I think) saying that the tool icons weren’t showing up on their Fedora system. Could it be that the Fedora package is missing a runtime dependency on the qtsvg 5 (specifically the plugins it provides)?

[musicinmybrain]

Thanks for the PR. I see you also removed the previous developer_name tag, but won’t this degrade compatibility with current versions, considering that 1.0 has not been released yet? Would it be fine to keep developer_name for now (alongside the new tag) until more distributions have updated to 1.0?

Annoyingly, appstreamcli validate emits a warning (W) when developer_name is present, and adding developer doesn’t change that. Also annoyingly, it fails (exits with nonzero status) when there are warnings.

On a completely unrelated note, the other day I saw a review (from ODRS I think) saying that the tool icons weren’t showing up on their Fedora system. Could it be that the Fedora package is missing a runtime dependency on the qtsvg 5 (specifically the plugins it provides)?

I just tested this by starting with a Fedora Server VM image from https://download.fedoraproject.org/pub/fedora/linux/releases/39/Server/x86_64/images/Fedora-Server-KVM-39-1.5.x86_64.qcow2, then installing the Basic Desktop group and Pencil2D. I was able to reproduce the problem, and installing qt5-qtsvg fixed it, so I’ll add a manual dependency. Normally, Qt library dependencies like this are handled automatically because something dynamically links one of their shared objects. I guess that didn’t happen because the plugins are conditionally dlopen’ed at runtime. Thanks for pointing this out.

[J5lx]

Ok so I just found out that while I was wondering how to deal with the compatibility issue, the problem actually resolved itself as not only was AppStream 1.0.0 released yesterday, but support for the developer tag was also backported to the 0.16 series as well, so I’ll just merge this now. Thanks again for the PR, and thank you for fixing the icon issue as well!