Merge pull request #10995 from kpayson64/upgrade_protobuf

composer.json

setup.py

src/php/composer.json

src/python/grpcio_health_checking/setup.py

src/python/grpcio_reflection/setup.py

src/python/grpcio_tests/setup.py

templates/composer.json.template

templates/src/php/composer.json.template

third_party/protobuf

tools/distrib/python/grpcio_tools/protoc_lib_deps.py

tools/distrib/python/grpcio_tools/setup.py

tools/run_tests/run_tests_matrix.py

tools/run_tests/sanity/check_submodules.sh