[CI] Add xgboost and scikit-learn to requirements

This should be added so we can test RBDT in the CI.

Author: guitargeek

requirements.txt

@@ -3,6 +3,8 @@
 # PyROOT: Interoperability with numpy arrays
 # TMVA: PyMVA interfaces
 numpy>=1.4.1
+scikit-learn
+xgboost
 
 # PyROOT: ROOT.Numba.Declare decorator
 numba>=0.47.0 ; python_version < "3.11" # See https://github.com/numba/numba/issues/8304