sktime#7865)

replaced 3.12 with 3.13 in pyrpject.toml for tensorflow's max python
version requirement

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#### Reference Issues/PRs
Fixes sktime#7858 
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#### What does this implement/fix? Explain your changes.
Changed `'tensorflow<2.17,>=2; python_version < "3.12"'` to
`'tensorflow<2.17,>=2; python_version < "3.13"'` everywhere in
`pyproject.toml`
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#### Does your contribution introduce a new dependency? If yes, which
one?
No
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#### Any other comments?
Referenced [Tensorflow's Release
Notes](https://github.com/tensorflow/tensorflow/releases/tag/v2.16.1)
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