v1.12.* should require protobuf >=6.31.1

[kho]

Details: d3194a3#r188889285

[kho]

Copied here for better visibility:

(Regarding _PROTOBUF_VERSION = "6.31.1" in WORKSPACE)

This bump in protobuf version is not reflected in https://github.com/tensorflow/metadata/blob/master/setup.py#L139. As a result, pip might install an older version of protobuf (e.g. required by an older version of tensorflow) and the latest version of tensorflow-metadata, which results in an import time failure.

Here's an example for reproducing the problem:

#!/bin/bash -e
mkdir /tmp/test_meta
cd /tmp/test_meta
uv venv --python=3.12
uv pip install tensorflow==2.18 tensorflow-metadata
uv run python -c 'from tensorflow_metadata import proto'

This will now install protobuf==5.29.6 (required by tensorflow==2.18.0) and lead to the following error:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/tmp/test_meta/.venv/lib/python3.12/site-packages/tensorflow_metadata/proto/__init__.py", line 16, in <module>
    from tensorflow_metadata.proto.v0 import (
  File "/tmp/test_meta/.venv/lib/python3.12/site-packages/tensorflow_metadata/proto/v0/anomalies_pb2.py", line 12, in <module>
    _runtime_version.ValidateProtobufRuntimeVersion(
  File "/tmp/test_meta/.venv/lib/python3.12/site-packages/google/protobuf/runtime_version.py", line 100, in ValidateProtobufRuntimeVersion
    _ReportVersionError(
  File "/tmp/test_meta/.venv/lib/python3.12/site-packages/google/protobuf/runtime_version.py", line 50, in _ReportVersionError
    raise VersionError(msg)
google.protobuf.runtime_version.VersionError: Detected incompatible Protobuf Gencode/Runtime versions when loading tensorflow_metadata/proto/v0/anomalies.proto: gencode 6.31.1 runtime 5.29.6. Runtime version cannot be older than the linked gencode version. See Protobuf version guarantees at https://protobuf.dev/support/cross-version-runtime-guarantee.