sage_bootstrap: Remove purported Python 2.6 support #20023
Description
- Apparently sage-bootstrap-python using python 2.6 is broken already - https://groups.google.com/g/sage-support/c/GniJKQ0MaMY/m/DugFUprJAwAJ
- Platforms such as RHEL 6 and Centos 6 reached their EOL at the end of 2020; and Docker-based testing of
centos-6no longer works
In this ticket, we
- delete
sage_bootstrap/compat/argparse.py - Change http://doc.sagemath.org/html/en/developer/packaging.html#checksums and any other related documentation (last modified in Installation manual: Fix documentation of python prerequisite (sage-bootstrap-python) #31192)
This is on top of #31419 so that we have to change README only once.
Depends on #29890
Depends on #31419
Depends on #31318
CC: @fchapoton @dimpase @embray @kiwifb @jdemeyer @slel @jhpalmieri
Component: build
Author: Dima Pasechnik, Matthias Koeppe
Branch/Commit: 8cd0bcc
Reviewer: Matthias Koeppe, Dima Pasechnik
Issue created by migration from https://trac.sagemath.org/ticket/20023