Move out of bionic.

[mgautierfr]

This is a tracking issue to move out of bionic build.

We still need to build libzim on bionic because we need to compile on glibc <= 2.28. This is enforced by the python "platform" definition and the last available platform is manylinux_2_28
(See original issue #595).

However:

• Bionic's eol is April, 2023
• Python 3.6 (which is the python version in Bionic) is eol December 2018.

There was the deadsnake ppa (https://launchpad.net/~deadsnakes/+archive/ubuntu/ppa) to install a "recent" python 3.8 on Bionic but it seems the repository for Bionic is no more (probably with Bionic's eol)

This means that kiwix-build is stuck with python 3.6, a 6 years old dead version.

A recent issue on manylinux is tracking the manylinux_2_34 status : pypa/manylinux#1585. Hopefully we will able to move to a more recent version of ubuntu soon.

Another way is to build libzim directly using manylinux_2_28 as the image contains python up to 3.12

[rgaudin]

I understand the problem as:

• we need bionic because we publish pylibzim for manylinux_2_28 (see glibc version mismatch building wheel on py37 aarch64 openzim/python-libzim#170 (comment))
• bionic-related files have been removed from the PPA so we cannot rebuild our bionic image to update it.
• without the PPA, bionic is limited to python 3.6
• kiwix-build code is 3.8+

Possible solutions:

• ❌ publish pylibzim for manylinux_2_31. There is no image and manylinux is looking at creating one for 2_34. We don't know when and it wont support bullseye
• install recent python from source inside our bionic image
• build (kiwix-build) inside manylinux_2_28

@mgautierfr I think it's up to you. I can't think of any strong reasons in favor of one or the other. Added this topic to the hackathon (broader topic) should we have not decided by then