[CI] Disable PyMVA so we can support the newest TensorFlow versions

Right now we don't support the newest TensorFlow releases after the 2.15
series, initially released in November 2023 [1].

Support for TensorFlow>=2.16 is worked on [2], but it's difficult to
make progress if we don't have TensorFlow>=2.16 in our CI images.
And we veto it from our CI image via the `requirements.txt` mechanism.

To continue, we need to temporarily disable PyMVA in the CI, such that
we can include the newest TensorFlow version in our images, and then
re-enable it in the PR that fixes support for the newest TensorFlow.
This is what is done in this commit.

Supporting the newest TensorFlow became a bit more important now that we
also have another feature besides PyMVA that uses TensorFlow: the
RBatchGenerator. It would not good to hold off testing the
actively-developed RBatchGenerator on newer TensorFlow versions, just
because PyMVA prevents us from installing these on our CI.

[1] https://github.com/tensorflow/tensorflow/releases
[2] #15790

Author: guitargeek

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

@@ -91,7 +91,7 @@ testing=ON
 tmva-cpu=ON
 tmva-gpu=OFF
 tmva-cudnn=OFF
-tmva-pymva=ON
+tmva-pymva=OFF
 tmva-rmva=OFF
 tmva-sofie=OFF
 tmva=ON

.github/workflows/root-ci-config/buildconfig/ubuntu2404-cuda.txt

@@ -6,7 +6,7 @@ tmva=ON
 tmva-cpu=ON
 tmva-gpu=ON
 tmva-cudnn=ON
-tmva-pymva=ON
+tmva-pymva=OFF
 fortran=OFF
 gdml=OFF
 spectrum=OFF

requirements.txt

@@ -11,7 +11,7 @@ onnx
 
 # TMVA: PyMVA interfaces
 scikit-learn
-tensorflow<2.16 ; python_version < "3.12"
+tensorflow ; python_version < "3.13" # TensorFlow doesn't support Python 3.13 yet
 torch
 xgboost