Bump tensorflow from 2.11.0 to 2.12.1 in /examples/keras-tract-tf2

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 2.11.0 to 2.12.1.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.11.0...v2.12.1)

---
updated-dependencies:
- dependency-name: tensorflow
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

examples/keras-tract-tf2/requirements.txt

@@ -1,4 +1,4 @@
-tensorflow==2.11.0
+tensorflow==2.12.1
 numpy==1.24.4
 tf2onnx==1.13.0
 tract==0.21.6