test(translate): add py2 deprecation warning; bump copyright year to 2020; add 3.8 unit tests (via synth)

[yoshi-automation]

This PR was generated using Autosynth. 🌈

Log from Synthtool

synthtool > Executing /tmpfs/src/git/autosynth/working_repo/translate/synth.py.
synthtool > Ensuring dependencies.
synthtool > Pulling artman image.
latest: Pulling from googleapis/artman
Digest: sha256:c773192618c608a7a0415dd95282f841f8e6bcdef7dd760a988c93b77a64bd57
Status: Image is up to date for googleapis/artman:latest
synthtool > Cloning googleapis.
synthtool > Running generator for google/cloud/translate/artman_translate_v3beta1.yaml.
synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/translate-v3beta1.
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/translate/v3beta1/translation_service.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/translate-v3beta1/google/cloud/translate_v3beta1/proto/translation_service.proto
synthtool > Placed proto files into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/translate-v3beta1/google/cloud/translate_v3beta1/proto.
synthtool > Replaced 'google.cloud.translation_v3beta1.proto' in google/cloud/translate_v3beta1/proto/translation_service_pb2_grpc.py.
synthtool > Running generator for google/cloud/translate/artman_translate_v3.yaml.
synthtool > Generated code into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/translate-v3.
synthtool > Copy: /home/kbuilder/.cache/synthtool/googleapis/google/cloud/translate/v3/translation_service.proto to /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/translate-v3/google/cloud/translate_v3/proto/translation_service.proto
synthtool > Placed proto files into /home/kbuilder/.cache/synthtool/googleapis/artman-genfiles/python/translate-v3/google/cloud/translate_v3/proto.
synthtool > Replaced 'google.cloud.translation_v3.proto' in google/cloud/translate_v3/proto/translation_service_pb2_grpc.py.
synthtool > Replaced "record delimiters are ':raw-latex:`\\\\n`' instead of\n          ':raw-latex:`\\\\r`:raw-latex:`\\\\n`'." in google/cloud/translate_v3beta1/proto/translation_service_pb2.py.
synthtool > Replaced "record delimiters are ':raw-latex:`\\\\n`' instead of\n          ':raw-latex:`\\\\r`:raw-latex:`\\\\n`'." in google/cloud/translate_v3/proto/translation_service_pb2.py.
synthtool > Replaced '__doc__ = """Attributes:' in google/cloud/translate_v3beta1/proto/translation_service_pb2.py.
synthtool > Replaced '__doc__ = """Attributes:' in google/cloud/translate_v3/proto/translation_service_pb2.py.
synthtool > Replaced 'This field has the same length as \\[``contents`\n\\s+`\\]\\[google\\.cloud\\.translation\\.v3beta1\\.TranslateTextRequest\\.conte\n\\s+nts\\]\\.' in google/cloud/translate_v3beta1/proto/translation_service_pb2.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==19.3b0
black docs google tests noxfile.py setup.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3/gapic/translation_service_client_config.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3/gapic/transports/translation_service_grpc_transport.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3/types.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3beta1/__init__.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3/proto/translation_service_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3beta1/gapic/translation_service_client_config.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3beta1/gapic/transports/translation_service_grpc_transport.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3/gapic/translation_service_client.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3beta1/gapic/translation_service_client.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3beta1/proto/translation_service_pb2_grpc.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3beta1/types.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/noxfile.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/tests/unit/gapic/v3/test_translation_service_client_v3.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/tests/unit/gapic/v3beta1/test_translation_service_client_v3beta1.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3/proto/translation_service_pb2.py
reformatted /tmpfs/src/git/autosynth/working_repo/translate/google/cloud/translate_v3beta1/proto/translation_service_pb2.py
All done! ✨ 🍰 ✨
18 files reformatted, 19 files left unchanged.
Session blacken was successful.
synthtool > Cleaned up 3 temporary directories.
synthtool > Wrote metadata to synth.metadata.

[busunkim96]

Headers appear to have changed. 🤔 Unit tests are failing across versions.

   Expected: request(data='req-data-boring', headers={'Accept-Encoding': 'gzip', 'X-Goog-API-Client': 'gl-python/3.6.9 grpc/1.25.0 gax/1.14.3 gapic/2.0.0 gccl/2.0.0', 'User-Agent': 'gl-python/3.6.9 grpc/1.25.0 gax/1.14.3 gapic/2.0.0 gccl/2.0.0'}, method='GET', url='https://translation.googleapis.com/language/translate/v2/rainbow')
E   Actual: request(data='req-data-boring', headers={'Accept-Encoding': 'gzip', 'X-Goog-API-Client': 'gl-python/3.6.9 grpc/1.25.0 gax/1.14.3 gapic/2.0.0 gccl/2.0.0', 'User-Agent': 'gl-python/3.6.9 grpc/1.25.0 gax/1.14.3 gapic/2.0.0 gccl/2.0.0'}, method='GET', timeout=None, url='https://translation.googleapis.com/language/translate/v2/rainbow')

<string>:3: AssertionError