The only stable and supported version(s), by definition, are 3.0.x. And it has been like that in quite a while so there has been plenty of time already to start a migration.
Running versions of the addons that differ from the core version has never been supported or recommended.
Trying to get that to work is a waste of time so you must not complain when it doesn’t work out.
The current stable (and supported) version is 3.0.1 so install that.
If you want to use some new ZWave device that is not contained in there that is not a feature of that software version.
So if you insist on getting and operating ultra new hardware (note: that’s your deliberate decision, noone has to do that !) you implicitly decide to use a beta software part/feature, and that, for obvious reasons, is not part of any “stable” tagged software.
I know you dislike that view and yes it has some annoying implications but that is what it is.
In that case you or anyone can install the latest 3.1 milestone.
Anyone, when you setup or upgrade to a new OH use packages (to contain .kar’s) for addons right away so you don’t make yourself dependent on any online resource whatsoever. That’s not so clever even if there wasn’t any Bintray issue, even more so for a system that is designed to run autonomously.