build(deps-dev): update tensorflow requirement

Updates the requirements on [tensorflow](https://github.com/tensorflow/tensorflow) to permit the latest version.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.18.0...v2.20.0)

---
updated-dependencies:
- dependency-name: tensorflow
  dependency-version: 2.20.0
  dependency-type: direct:development
...

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

Author: dependabot[bot]

pyproject.toml

@@ -162,7 +162,7 @@ pin_tensorflow_cpu = [
   "tensorflow-cpu~=2.18.0",
 ]
 pin_tensorflow_gpu = [
-  "tensorflow~=2.18.0",
+  "tensorflow>=2.18,<2.21",
 ]
 pin_pytorch_cpu = [
   "torch~=2.8.0",