update python to 3.10 and Keras to 3.6

[sachinprasadhs]

Description of the change

• Updated python version from 3.9 to 3.10
• Updated Keras version from 3.5 to 3.6, since couple of models use dot_product_attention, which was introduced in keras from 3.6 version.
• Updated stale script to run only on main repo and skip forked repo and added operations-per-run to cover all the issues and PRs.

Reference

Colab Notebook

Checklist

• I have added all the necessary unit tests for my change.
• I have verified that my change does not break existing code and works with all backends (TensorFlow, JAX, and PyTorch).
• My PR is based on the latest changes of the main branch (if unsure, rebase the code).
• I have followed the Keras Hub Model contribution guidelines in making these changes.
• I have followed the Keras Hub API design guidelines in making these changes.
• I have signed the Contributor License Agreement.