tests/check-gendoc

packaging: update the certifi dependency

Not sure if this helps with recent certificate issues[1], but we might as well
keep this modern.

Note that certifi no longer claims py2 support, and there's a PR to add it back
in[2].  Py2 support was dropped in 2020.04.05.2 (which predates what's being
updated here).  None of the *.py files have changed since the 2020.6.20 release,
and I was able to call `certifi.where()` in both a virtualenv and with
`hg debugshell` from an MSI install with this version, so we shouldn't be any
worse off than before.

[1] https://foss.heptapod.net/mercurial/tortoisehg/thg/-/issues/5745
[2] https://github.com/certifi/python-certifi/pull/154

Differential Revision: https://phab.mercurial-scm.org/D11609

#!/bin/sh
HGENCODING=UTF-8
export HGENCODING

echo ".. -*- coding: utf-8 -*-" > gendoc.txt
echo "" >> gendoc.txt
LANGUAGE=$1 "$PYTHON" "$TESTDIR/../doc/gendoc.py" >> gendoc.txt 2> /dev/null || exit

echo "checking for parse errors"
"$PYTHON" "$TESTDIR/../doc/docchecker" gendoc.txt
"$PYTHON" "$TESTDIR/../doc/runrst" html gendoc.txt /dev/null