Version is that of any child branches marked with IsReleaseBranch (except if they have no commits of their own).
BaseVersionSource is the commit where the child branch was created.
Version is extracted from all tags on the
master branch which are valid.
BaseVersionSource is the tag's commit (same as base strategy).
Increments if the tag is not the current commit (same as base strategy).
public class TrackReleaseBranchesVersionStrategy : VersionStrategyBase, IVersionStrategy