fix: add python 2.7 deprecation warning (via synth)

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Log from Synthtool

2020-03-19 05:18:39,010 synthtool > Executing /tmpfs/src/git/autosynth/working_repo/synth.py.
2020-03-19 05:18:39,065 synthtool > Ensuring dependencies.
2020-03-19 05:18:39,069 synthtool > Pulling artman image.
latest: Pulling from googleapis/artman
Digest: sha256:5ef340c8d9334719bc5c6981d95f4a5d2737b0a6a24f2b9a0d430e96fff85c5b
Status: Image is up to date for googleapis/artman:latest
2020-03-19 05:18:40,397 synthtool > Cloning googleapis.
2020-03-19 05:18:40,725 synthtool > Running generator for google/cloud/scheduler/artman_cloudscheduler_v1beta1.yaml.
2020-03-19 05:18:55,555 synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1beta1.
2020-03-19 05:18:55,556 synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/scheduler/v1beta1/job.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1beta1/google/cloud/scheduler_v1beta1/proto/job.proto
2020-03-19 05:18:55,556 synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/scheduler/v1beta1/cloudscheduler.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1beta1/google/cloud/scheduler_v1beta1/proto/cloudscheduler.proto
2020-03-19 05:18:55,557 synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/scheduler/v1beta1/target.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1beta1/google/cloud/scheduler_v1beta1/proto/target.proto
2020-03-19 05:18:55,557 synthtool > Placed proto files into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1beta1/google/cloud/scheduler_v1beta1/proto.
2020-03-19 05:18:55,579 synthtool > Replaced 'google-cloud-cloudscheduler' in google/cloud/scheduler_v1beta1/gapic/cloud_scheduler_client.py.
2020-03-19 05:18:55,579 synthtool > Running generator for google/cloud/scheduler/artman_cloudscheduler_v1.yaml.
2020-03-19 05:19:10,290 synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1.
2020-03-19 05:19:10,291 synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/scheduler/v1/job.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1/google/cloud/scheduler_v1/proto/job.proto
2020-03-19 05:19:10,291 synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/scheduler/v1/cloudscheduler.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1/google/cloud/scheduler_v1/proto/cloudscheduler.proto
2020-03-19 05:19:10,291 synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/scheduler/v1/target.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1/google/cloud/scheduler_v1/proto/target.proto
2020-03-19 05:19:10,292 synthtool > Placed proto files into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/cloudscheduler-v1/google/cloud/scheduler_v1/proto.
2020-03-19 05:19:10,319 synthtool > Replaced 'google-cloud-cloudscheduler' in google/cloud/scheduler_v1/gapic/cloud_scheduler_client.py.
.coveragerc
.flake8
.github/CONTRIBUTING.md
.github/ISSUE_TEMPLATE/bug_report.md
.github/ISSUE_TEMPLATE/feature_request.md
.github/ISSUE_TEMPLATE/support_request.md
.github/PULL_REQUEST_TEMPLATE.md
.github/release-please.yml
.gitignore
.kokoro/build.sh
.kokoro/continuous/common.cfg
.kokoro/continuous/continuous.cfg
.kokoro/docs/common.cfg
.kokoro/docs/docs.cfg
.kokoro/presubmit/common.cfg
.kokoro/presubmit/presubmit.cfg
.kokoro/publish-docs.sh
.kokoro/release.sh
.kokoro/release/common.cfg
.kokoro/release/release.cfg
.kokoro/trampoline.sh
CODE_OF_CONDUCT.md
CONTRIBUTING.rst
LICENSE
MANIFEST.in
docs/_static/custom.css
docs/_templates/layout.html
docs/conf.py.j2
noxfile.py.j2
renovate.json
setup.cfg
Running session blacken
Creating virtual environment (virtualenv) using python3.6 in .nox/blacken
pip install black==19.3b0
black docs google tests noxfile.py setup.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/gapic/enums.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/gapic/cloud_scheduler_client_config.py
reformatted /tmpfs/src/git/autosynth/working_repo/docs/conf.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/gapic/transports/cloud_scheduler_grpc_transport.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/proto/cloudscheduler_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/proto/job_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/gapic/cloud_scheduler_client.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/proto/target_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/types.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/proto/job_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/gapic/cloud_scheduler_client_config.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/gapic/enums.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/proto/cloudscheduler_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/gapic/transports/cloud_scheduler_grpc_transport.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/gapic/cloud_scheduler_client.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/proto/cloudscheduler_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/proto/job_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1/proto/target_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/proto/target_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/types.py
reformatted /tmpfs/src/git/autosynth/working_repo/noxfile.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/proto/cloudscheduler_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/proto/job_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/google/cloud/scheduler_v1beta1/proto/target_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/tests/unit/gapic/v1/test_cloud_scheduler_client_v1.py
reformatted /tmpfs/src/git/autosynth/working_repo/tests/unit/gapic/v1beta1/test_cloud_scheduler_client_v1beta1.py
All done! ✨ 🍰 ✨
31 files reformatted, 8 files left unchanged.
Session blacken was successful.
2020-03-19 05:19:16,069 synthtool > Wrote metadata to synth.metadata.