Add support for support branches about vststasks

[ycamargo]

I really don't like the idea of support branches. I do prefer to fork the repo if the old supported version get, in some point in time, the need to be changed/fixed and those changes would not be reflected on the current version. Why should I keep in the same repo those two different kind of animals? Looks like an "old days" branching strategy. And even with versions forked in different repos, git will always let you merge changes (cherry-picked) from one repo to another, and these could be merged into a feature or hotfix branch and, then, follow the normal git flow to be merged onto develop and master.