BigQuery: Additional clustering metrics for BQML K-means models (via synth).

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Here's the log from Synthtool:

synthtool > Executing /tmpfs/src/git/autosynth/working_repo/bigquery/synth.py. synthtool > Ensuring dependencies. synthtool > Pulling artman image. latest: Pulling from googleapis/artman Digest: sha256:a684d40ba9a4e15946f5f2ca6b4bd9fe301192f522e9de4fff622118775f309b Status: Image is up to date for googleapis/artman:latest synthtool > Cloning googleapis. synthtool > Running generator for google/cloud/bigquery/artman_bigquery_v2.yaml. synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigquery-v2. synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/bigquery/v2/model_reference.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigquery-v2/google/cloud/bigquery_v2/proto/model_reference.proto synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/bigquery/v2/model.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigquery-v2/google/cloud/bigquery_v2/proto/model.proto synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/bigquery/v2/standard_sql.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigquery-v2/google/cloud/bigquery_v2/proto/standard_sql.proto synthtool > Placed proto files into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigquery-v2/google/cloud/bigquery_v2/proto. synthtool > Replaced '"""Attributes:' in google/cloud/bigquery_v2/proto/model_pb2.py. synthtool > No replacements made in google/cloud/bigquery_v2/proto/*.py for pattern [“”], maybe replacement is not longer needed? Running session blacken Creating virtualenv using python3.6 in .nox/blacken pip install black black docs google samples tests noxfile.py setup.py reformatted /tmpfs/src/git/autosynth/working_repo/bigquery/google/cloud/bigquery_v2/gapic/enums.py reformatted /tmpfs/src/git/autosynth/working_repo/bigquery/google/cloud/bigquery_v2/proto/model_pb2_grpc.py reformatted /tmpfs/src/git/autosynth/working_repo/bigquery/google/cloud/bigquery_v2/proto/model_reference_pb2_grpc.py reformatted /tmpfs/src/git/autosynth/working_repo/bigquery/google/cloud/bigquery_v2/proto/model_reference_pb2.py reformatted /tmpfs/src/git/autosynth/working_repo/bigquery/google/cloud/bigquery_v2/proto/standard_sql_pb2_grpc.py reformatted /tmpfs/src/git/autosynth/working_repo/bigquery/google/cloud/bigquery_v2/types.py reformatted /tmpfs/src/git/autosynth/working_repo/bigquery/google/cloud/bigquery_v2/proto/standard_sql_pb2.py reformatted /tmpfs/src/git/autosynth/working_repo/bigquery/google/cloud/bigquery_v2/proto/model_pb2.py All done! ✨ 🍰 ✨ 8 files reformatted, 105 files left unchanged. Session blacken was successful. synthtool > Cleaned up 0 temporary directories. synthtool > Wrote metadata to synth.metadata.