Comment 1 for bug 1936871

Ubuntu 20.04 ships squashfs-tools 4.4 whereas on 18.04/16.04 we have 4.3 - I notice in https://github.com/plougher/squashfs-tools/blob/master/CHANGES#L9 that upstream says 4.4 introduces reproducible builds by default for mksquashfs so perhaps we should be using this in the review-tools snap and snapcraft instead so we can all align on the same version? Or since review-tools and snapcraft are both base: core18, can the store instead just use the review-tools snap directly?