[LyX/master] Python runtime detection requirement upgraded to 3.8

[José Matos]

On Wed, 2024-06-12 at 10:06 +0200, Pavel Sanda wrote:
> Hi Jose,
> 
> bumping p3 version requirements and dropping p2 should go into
> RELEASE-NOTES and specific version should be fixed in
> INSTALL/README...
> 
> Pavel

For the moment I updated the INSTALL document.

I moved up the reference to Python to the regular requirements. Because
that is a regular requirement.

I have also removed the reference to the two programs because I have no
idea about it means. I suspect that it could be related to us
supporting both Python 2 and 3...

-- 
José Abílio