Upstream says no release will be made anymore, and that packagers should get a snapshot from git: https://github.com/canonical/lightdm/commit/80147e515513261226d01a32c8b0c819f84e21e8 1.30.0 was released _over_ 3 years ago and there's plenty of commits afterwards, where hopefully some of the reported bugs could be fixed too: https://bugs.gentoo.org/buglist.cgi?quicksearch=x11-misc%2Flightdm
Well they ended up making an official release after all, https://github.com/canonical/lightdm/commit/4b10d07b7bf87668a245b438b5ffc82e3956bd1c https://github.com/canonical/lightdm/tags
*** Bug 859871 has been marked as a duplicate of this bug. ***
Fixed by c3d186d7c6ff4c2a2f01a51cf992a3c5eaf38b5a.