Fix lyxpak to be Python 3 compatible

[José Matos]

On Wed, 2023-12-06 at 14:21 -0500, Scott Kostyshak wrote:
> Thanks for the quick fix!
> 
> It's in master at 9143878e.
> 
> Next time, it might be easier if you make the patch with
> 
>   git format-patch HEAD^
> 
> This way you can add a commit message.
> 
> Scott

Thank you for the hint. I will use it. :-)
-- 
José Abílio