Or Tycho could step up and take the lead :-)
I'm not sure it's a wise thing; the coupling between Tycho and Platform is huge; and Platform will make its choice based on its huge legacy, independently of Tycho. So if Tycho takes the lead but both go to a different direction, we can say a definitive goodbye to a proper way of linking issues.
While github do not directly have a concept of "blocking" ticket as far
as as I know you can use labels and references to organize you in a much
more flexible way [1] gives a good overview.
That's nothing semantic, all textual conventions, it's really weak!
gitlab seems to support it
as a separate reference type [2]
That seems really good!
In the end its all about how you organize your work, having a
"blocked-by" is meaningless unless there's someone really managing work
and pushing things forward to resolve blockers.
Many committers do look at those blocked-by to manage their own work. I personally look at these links every time I open a bugzilla issue.