run: Don't allow chroot()
run: Don't allow chroot()

If we don't allow pivot_root() then there seems no reason why we should
allow chroot().

Partially fixes GHSA-67h7-w3jq-vh4q.

Signed-off-by: Simon McVittie <0e1aea601907c1a85c2dc96e5ea37e23c58d2e9b@collabora.com>

flatpak/flatpak,flatpak/flatpak,flatpak/flatpak,flatpak/flatpak,flatpak/flatpak