[flatpak] Please update to depend on a more recent GNOME runtime

[rscm]

Info: el tiempo de ejecución org.gnome.Platform rama 46 terminó su vida útil, con motivo:
The GNOME 46 runtime is no longer supported as of April 17, 2025. Please ask your application developer to migrate to a supported platform.
Info: aplicaciones que usan este tiempo de ejecución:
   io.github.mightycreak.Diffuse

Thanks

[MightyCreak]

Fixed with #250