remove scipy==1.2.1 requirement when new statsmodel package releases

Waiting on https://github.com/statsmodels/statsmodels/issues/5620 to solve https://github.com/statsmodels/statsmodels/issues/5747 so I can revert https://github.com/MarvinT/morphs/pull/76/commits/4053bd451411d0bd164862ce91752fcec0ac5996