message: Add GITHUB_PAT to pass a token, to have a higher limit to pull from R repo
  Travis CI set a limit to pull unless a GITHUB_PAT is passed. With
  GITHUB_PAT we should have 5000/hour (vs. 60/hour).
diff: @@ -59,8 +59,8 @@ jobs:
  export TENSORFLOW_INSTALL="tensorflow==1.13.0rc2"
  docker run -e TENSORFLOW_INSTALL=${TENSORFLOW_INSTALL} -i -t --rm -v $PWD:/v -w /v --net=host ubuntu:14.04 bash -x -e /v/.travis/python.release.sh --nightly ${TRAVIS_BUILD_NUMBER}
  ls -la wheelhouse/*.whl
  - docker run -e TENSORFLOW_INSTALL=${TENSORFLOW_INSTALL} -i -t --rm -v $PWD:/v -w /v --net=host ubuntu:16.04 bash -x -e /v/.travis/install.test.sh
  - docker run -e TENSORFLOW_INSTALL=${TENSORFLOW_INSTALL} -i -t --rm -v $PWD:/v -w /v --net=host ubuntu:18.04 bash -x -e /v/.travis/install.test.sh
  + docker run -e TENSORFLOW_INSTALL=${TENSORFLOW_INSTALL} -e GITHUB_PAT=${GITHUB_PAT} -i -t --rm -v $PWD:/v -w /v --net=host ubuntu:16.04 bash -x -e /v/.travis/install.test.sh
  + docker run -e TENSORFLOW_INSTALL=${TENSORFLOW_INSTALL} -e GITHUB_PAT=${GITHUB_PAT} -i -t --rm -v $PWD:/v -w /v --net=host ubuntu:18.04 bash -x -e /v/.travis/install.test.sh
  if [[ ( ${TRAVIS_BRANCH} == "master" ) && ( ${TRAVIS_EVENT_TYPE} != "pull_request" ) ]]; then
  ls wheelhouse/*.whl
  twine upload wheelhouse/*.whl
  