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

[José Matos]

On Thu, 2024-06-13 at 10:41 +0200, Pavel Sanda wrote:
> I wouldn't have this courage :)
> 
> You are joining the debate little late, but you can try to convince
> Jose to delay his version bumping towards end of the cycle. Your mint
> 18 lifetime ends with some 2-3 years IIRC, so you'll need to update
> then.
> 
> Pavel

I am not a specialist in Mint (or any other Debian derivative
distribution) but as far as I understand Mint can use Ubuntu
repositories. In those repositories Python 3.8 is available.

I saw examples about this when searching for this specific issue.
There are several repositories that have this.

One simple hypothesis is the deadsnakes ppa:

Source:
How to Install Python 3.8 on Ubuntu 18.04
https://linuxize.com/post/how-to-install-python-3-8-on-ubuntu-18-04/#installing-python-38-on-ubuntu-with-apt

"The same steps apply for Ubuntu 16.04 and any Ubuntu-based
distribution, including Kubuntu, Linux Mint, and Elementary OS."

The repository is legitimate, developed by Debian and Python
developers, and so a reliable source.

Since we only use the python distribution and not any external package
the solution is as simple as to install Python 3.8.
-- 
José Abílio