Fix packagist affected range

Based on the discussion in !121 (comment 232410694), this MR changes the affected_range of packagist packages to remove differences between the affected versions listed by the new Gemnasium and the ones listed by the Gemnasium API. It essentially removes ambiguity by adding -stable or -dev tags to the versions. See gemnasium!48 on what causes this difference.

In one case, there was also an affected range missing entirely.

Warning! This MR makes the new Gemnasium consistent with the Gemnasium API with the affected versions it reports, but that doesn't necessarily mean that the affected ranges are accurate. There'll be another MR to address or, when in doubt, to update/extend the ranges to include pre-releases.