Releasing version 1.0 seems like a "big deal".
It usually means that a software is stable and well tested.
I am not sure I can say that the current version is really mature and for sure there are a lot of bugs that need to be fixed (with your help).
On the other hand, version 1.0 marks a new chapter for Groot, i.e. compatibility with version 3.X of BehaviorTree.Cpp, that IS stable.
Do not hesitate to report bugs.
Cheers
Davide