Fix metadata for the new appstream validator

[sonnyp]

No description provided.

[sonnyp]

blue 1 and 4 from the GNOME color palette

https://docs.flathub.org/blog/introducing-app-brand-colors/

[sonnyp]

ximion/appstream#617

I want to see if upper case is a blocker on Flathub

[bbhtt]

We don't validate developer-id on Flathub, but upstream appstream is forbids it like you found.

[AkshayWarrier]

I ran flatpak run --command=flatpak-builder-lint org.flatpak.Builder appstream data/app.metainfo.xml and I get the following

E: @app_id@:3: cid-punctuation-prefix @app_id@
   The component ID starts with punctuation. This is not allowed.

E: @app_id@:3: cid-desktopapp-is-not-rdns @app_id@
   The component ID is not a reverse domain-name. Please update the ID to avoid future issues and
   be compatible with all AppStream implementations.
   You may also consider to update the name of the accompanying .desktop file to follow the latest
   version of the Desktop-Entry specification and use a rDNS name for it as well. In any case, do
   not forget to mention the new desktop-entry in a <launchable/> tag for this component to keep
   the application launchable from software centers and the .desktop file data associated with the
   metainfo data.

E: @app_id@:3: cid-invalid-character @app_id@: '@'
   The component ID contains an invalid character. Only ASCII characters, dots and numbers are
   permitted.

I: @app_id@:6: developer-id-invalid com.github.AkshayWarrier
   The developer-ID is invalid. It should be an rDNS string identifying the developer, or a
   Fediverse handle. It must also only contain lowercase ASCII letters, numbers and punctuation.

I: @app_id@:61: nonstandard-gnome-extension kudos
   This tag is a GNOME-specific extension to AppStream and not part of the official specification.
   Do not expect it to work in all implementations and in all software centers.

are these all normal?

[sonnyp]

yes - that's because you give it the non "compiled" metainfo where @app_id@ hasn't been replaced by meson