message: Add the flatbuffers python library to the Kokoro build VMs
diff: @@ -143,6 +143,7 @@ function install_pip_deps {
  ${SUDO_CMD} ${PIP_CMD} install scipy
  ${SUDO_CMD} ${PIP_CMD} install scikit-learn
  ${SUDO_CMD} ${PIP_CMD} install --upgrade tb-nightly
  + ${PIP_CMD} install --user --upgrade flatbuffers
  ${PIP_CMD} install --user --upgrade attrs
  ${PIP_CMD} install --user --upgrade tf-estimator-nightly
  ${PIP_CMD} install --user --upgrade "future>=0.17.1"
  @@ -166,6 +167,7 @@ function install_ubuntu_16_pip_deps {
  # LINT.IfChange(ubuntu_16_pip_installations)
  "${PIP_CMD}" install astunparse==1.6.3 --user
  "${PIP_CMD}" install --user --upgrade attrs
  + "${PIP_CMD}" install --user --upgrade flatbuffers
  "${PIP_CMD}" install keras_preprocessing==1.1.0 --no-deps --user
  "${PIP_CMD}" install numpy==1.16.0 --user
  "${PIP_CMD}" install --user --upgrade "future>=0.17.1"
  @@ -220,6 +222,7 @@ function install_macos_pip_deps {
  ${SUDO_CMD} ${PIP_CMD} install h5py==2.10.0
  ${SUDO_CMD} ${PIP_CMD} install --upgrade grpcio
  ${SUDO_CMD} ${PIP_CMD} install --upgrade tb-nightly
  + ${PIP_CMD} install --user --upgrade flatbuffers
  ${PIP_CMD} install --user --upgrade attrs
  # b/156523241
  ${PIP_CMD} install --force-reinstall --user --upgrade tf-estimator-nightly
  