bump version to 3.3.1
bump version to 3.3.1

ibab/root_numpy,ndawe/root_numpy,ibab/root_numpy,rootpy/root_numpy,ndawe/root_numpy,scikit-hep/root_numpy,scikit-hep/root_numpy,ndawe/root_numpy,ndawe/root_numpy,rootpy/root_numpy,ibab/root_numpy,scikit-hep/root_numpy,ibab/root_numpy,scikit-hep/root_numpy,rootpy/root_numpy,rootpy/root_numpy