[ci] Enable tmva-pymva again

This should work now that the PyKeras method is removed

Author: guitargeek

.github/workflows/root-ci-config/buildconfig/global.txt

@@ -90,7 +90,7 @@ testing=ON
 tmva-cpu=ON
 tmva-gpu=OFF
 tmva-cudnn=OFF
-tmva-pymva=OFF
+tmva-pymva=ON
 tmva-rmva=OFF
 tmva-sofie=OFF
 tmva=ON