fix flathub remote url in distro.yml

[Psycojoker]

Hello,

While following this documentation and running the command:

flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo

I ended up with the error:

Warning: Could not update extra metadata for 'flathub': GPG verification enabled, but no summary found (check that the configured URL in remote config is correct)

And failed to install any application with it.

Reading this issue: https://github.com/flatpak/flatpak/issues/1967#issuecomment-413323832 turns out the .dl part of the url needs to be removed and it fixed my problems.

Kind regards,

[AsciiWolf]

Thanks for reporting the issue! This should ideally be resolved on the Flathub side. I may be wrong, but I thought that the dl. subdomain was preferred over just flathub.org because it was on a CDN. I am however not sure whether this still is the case.

[AsciiWolf]

@Psycojoker Is this still a problem?