message: Change to `if branch = master` for nightly build
  Was `if branch = travis`, need to change to `if branch = travis`
diff: @@ -122,7 +122,7 @@ jobs:
  - docker run -i -t --rm -v ${PWD}:/working_dir -w /working_dir --net=host ${TEST_R_IMAGE} bash -x /working_dir/.travis/r.test.sh ${PYTHON_VERSION}
  - stage: nightly
  name: "Nightly Release"
  - if: branch = travis
  + if: branch = master
  script:
  - export TENSORFLOW_IO_VERSION=0.3.0.dev${TRAVIS_BUILD_NUMBER}
  - docker run -i -t --rm -v ${PWD}:/working_dir -w /working_dir tensorflow/tensorflow:custom-op pip download --index-url https://test.pypi.org/simple/ tensorflow-io-nightly==${TENSORFLOW_IO_VERSION} --no-deps -d artifacts/
  