gitlab: force allow use of pip in Cirrus jobs

gitlab: force allow use of pip in Cirrus jobs

Python is transitioning to a world where you're not allowed to use 'pip
install' outside of a virutal env by default. The rationale is to stop
use of pip clashing with distro provided python packages, which creates
a major headache on distro upgrades.

All our CI environments, however, are 100% disposable so the upgrade
headaches don't exist. Thus we can undo the python defaults to allow
pip to work.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Thomas Huth <thuth@redhat.com>
Message-id: 20240222114038.2348718-1-berrange@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>