feat(bigtable): add py2 deprecation warnings; standardize use of 'required' in docstrings (via synth)

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Log from Synthtool

synthtool > Executing /tmpfs/src/git/autosynth/working_repo/bigtable/synth.py.
synthtool > Ensuring dependencies.
synthtool > Pulling artman image.
latest: Pulling from googleapis/artman
Digest: sha256:264654a37596a44b0668b8ce6ac41082d713f6ee150b3fc6425fa78cc64e4f20
Status: Image is up to date for googleapis/artman:latest
synthtool > Cloning googleapis.
synthtool > Running generator for google/bigtable/artman_bigtable.yaml.
synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-v2.
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/bigtable/v2/bigtable.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-v2/google/cloud/bigtable_v2/proto/bigtable.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/bigtable/v2/data.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-v2/google/cloud/bigtable_v2/proto/data.proto
synthtool > Placed proto files into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-v2/google/cloud/bigtable_v2/proto.
synthtool > Running generator for google/bigtable/admin/artman_bigtableadmin.yaml.
synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-admin-v2.
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/bigtable/admin/v2/table.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-admin-v2/google/cloud/bigtable_admin_v2/proto/table.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/bigtable/admin/v2/common.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-admin-v2/google/cloud/bigtable_admin_v2/proto/common.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/bigtable/admin/v2/bigtable_instance_admin.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-admin-v2/google/cloud/bigtable_admin_v2/proto/bigtable_instance_admin.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/bigtable/admin/v2/instance.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-admin-v2/google/cloud/bigtable_admin_v2/proto/instance.proto
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/bigtable/admin/v2/bigtable_table_admin.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-admin-v2/google/cloud/bigtable_admin_v2/proto/bigtable_table_admin.proto
synthtool > Placed proto files into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/bigtable-admin-v2/google/cloud/bigtable_admin_v2/proto.
synthtool > Replaced "'google-cloud-bigtable-admin'" in google/cloud/bigtable_admin_v2/gapic/bigtable_instance_admin_client.py.
synthtool > Replaced "'google-cloud-bigtable-admin'" in google/cloud/bigtable_admin_v2/gapic/bigtable_table_admin_client.py.
synthtool > Replaced 'from google\\.cloud\\.bigtable\\.admin_v2.proto' in google/cloud/bigtable_admin_v2/proto/bigtable_table_admin_pb2.py.
synthtool > Replaced 'from google\\.cloud\\.bigtable\\.admin_v2.proto' in google/cloud/bigtable_admin_v2/proto/instance_pb2.py.
synthtool > Replaced 'from google\\.cloud\\.bigtable\\.admin_v2.proto' in google/cloud/bigtable_admin_v2/proto/bigtable_instance_admin_pb2.py.
synthtool > Replaced 'from google\\.cloud\\.bigtable\\.admin_v2.proto' in google/cloud/bigtable_admin_v2/proto/bigtable_table_admin_pb2_grpc.py.
synthtool > Replaced 'from google\\.cloud\\.bigtable\\.admin_v2.proto' in google/cloud/bigtable_admin_v2/proto/bigtable_instance_admin_pb2_grpc.py.
synthtool > Replaced '    __doc__ = bigtable_instance_admin_client.BigtableInstanceAdminClient.__doc__\n' in google/cloud/bigtable_admin_v2/__init__.py.
synthtool > Replaced 'if ``true_mutations`` is empty, and at most\n\n\\s*100000.' in google/cloud/bigtable_v2/gapic/bigtable_client.py.
synthtool > Replaced 'if ``false_mutations`` is empty, and at most\n\n\\s*100000.' in google/cloud/bigtable_v2/gapic/bigtable_client.py.
.coveragerc
.flake8
MANIFEST.in
docs/_static/custom.css
docs/_templates/layout.html
noxfile.py.j2
setup.cfg
Running session blacken
Creating virtual environment (virtualenv) using python3.6 in .nox/blacken
pip install black
black google tests docs
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/gapic/bigtable_table_admin_client_config.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/gapic/bigtable_instance_admin_client_config.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/gapic/enums.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/gapic/transports/bigtable_table_admin_grpc_transport.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/gapic/transports/bigtable_instance_admin_grpc_transport.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/bigtable_instance_admin_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/gapic/bigtable_instance_admin_client.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/gapic/bigtable_table_admin_client.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/common_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/common_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/bigtable_table_admin_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/instance_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/instance_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/table_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/types.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/gapic/bigtable_client.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/gapic/bigtable_client_config.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/gapic/transports/bigtable_grpc_transport.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/table_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/proto/bigtable_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/bigtable_table_admin_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/proto/data_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/types.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_admin_v2/proto/bigtable_instance_admin_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/tests/unit/gapic/v2/test_bigtable_client_v2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/proto/bigtable_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/tests/unit/gapic/v2/test_bigtable_instance_admin_client_v2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/tests/unit/gapic/v2/test_bigtable_table_admin_client_v2.py
reformatted /tmpfs/src/git/autosynth/working_repo/bigtable/google/cloud/bigtable_v2/proto/data_pb2.py
All done! ✨ 🍰 ✨
31 files reformatted, 42 files left unchanged.
Session blacken was successful.
synthtool > Wrote metadata to synth.metadata.