Bump the python group with 3 updates

Updates the requirements on [tensorflow](https://github.com/tensorflow/tensorflow), torch and [torch-xla](https://github.com/pytorch/xla) to permit the latest version.

Updates `tensorflow` to 2.20.0
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.18.1...v2.20.0)

Updates `torch` from 2.6.0 to 2.9.0+cpu

Updates `torch-xla` from 2.6.0 to 2.8.1
- [Release notes](https://github.com/pytorch/xla/releases)
- [Commits](pytorch/xla@v2.6.0...v2.8.1)

---
updated-dependencies:
- dependency-name: tensorflow
  dependency-version: 2.20.0
  dependency-type: direct:production
  dependency-group: python
- dependency-name: torch
  dependency-version: 2.9.0+cpu
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: python
- dependency-name: torch-xla
  dependency-version: 2.8.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: python
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements-torch-cuda.txt

@@ -5,7 +5,7 @@ tf2onnx
 # Torch with cuda support.
 # - torch is pinned to a version that is compatible with torch-xla.
 --extra-index-url https://download.pytorch.org/whl/cu121
-torch==2.9.0
+torch==2.9.0+cpu
 torch-xla==2.8.1;sys_platform != 'darwin'
 
 # Jax cpu-only version (needed for testing).

requirements.txt

@@ -2,13 +2,13 @@
 # Note: when the version of Tensorflow is changed, the version tf_keras must be
 # changed in .github/workflows/actions.yml (pip install --no-deps tf_keras).
 tensorflow-cpu~=2.18.1;sys_platform != 'darwin'
-tensorflow~=2.18.1;sys_platform == 'darwin'
+tensorflow~=2.20.0;sys_platform == 'darwin'
 tf2onnx
 
 # Torch.
 --extra-index-url https://download.pytorch.org/whl/cpu
-torch==2.6.0
-torch-xla==2.6.0;sys_platform != 'darwin'
+torch==2.9.0+cpu
+torch-xla==2.8.1;sys_platform != 'darwin'
 
 # Jax.
 # Pinned to 0.5.0 on CPU. JAX 0.5.1 requires Tensorflow 2.19 for saved_model_test.