ci: update actions/checkout to v3 and actions/setup-python to v4
ci: update actions/checkout to v3 and actions/setup-python to v4

Signed-off-by: Simon Deziel <eca3f1a14b730e70ce4898287e4fc2f9966fa3a6@canonical.com>

lxc/pylxd,lxc/pylxd