Summary

This PR aligns tensorflow-metadata (TFMD) with TensorFlow 2.21 dependencies, adds support for Python 3.12, and drops support for Python 3.9.

Changes

Python Version Support

• setup.py: Updated python_requires to ">=3.10,<4" and removed Python 3.9 classifiers.
• CI Workflows (test.yml, wheels.yml): Removed Python 3.9 from the build and test matrices.

Dependency Alignment & Build System

• Protobuf: Upgraded to 6.31.1 in WORKSPACE to align with TF 2.21.
• rules_python: Added rules_python (version 0.31.0) to WORKSPACE to resolve dependency resolution errors.
• bazel_skylib: Upgraded to 1.9.0 in WORKSPACE to resolve missing paths.is_normalized error required by Protobuf.
• Bazel Version: Relaxed the Bazel version check in WORKSPACE to 7.4.1 to allow local builds (CI remains at 7.7.0).
• Dummy Proxies: Created a dummy repository @compatibility_proxy in third_party/dummy_compatibility_proxy to satisfy transitive dependencies from rules_java without fetching large unused external packages.

Documentation

• RELEASE.md: Updated with these changes under the "Current Version" section.

Verification

Automated Tests

• All unit tests passed with pytest on Python 3.12.

Manual Verification

• Verified that bazel build //tensorflow_metadata/... completes successfully when using Clang 19 (--repo_env=CC=clang) to avoid .sframe relocation errors caused by GCC 15.