[Xfce-i18n] Fill out po headers (Project-Id-Version)

[André Miranda]

On 13/03/2019 08:49, scootergrisen wrote:
> Seems like the other ressources like gigoli mousepad orage in Xfce 
> Apps project just use:
> "Project-Id-Version: Xfce Apps\n"
>
> So maybe just use the same style as they do even though its incorrect.
> Maybe its something Transifex fills out automatically.
I couldn't find any documentation of how Transifex fills .po headers, 
probably we shouldn't rely on it.
With that script, eventually all projects will have the correct version.