message: With Kythe at latest version, we can use Bazel 4
diff: @@ -33,7 +33,7 @@ export BAZEL_CXXOPTS="-std=c++17"
  # Reduce the verbosity of progress output on CI
  export BAZEL_OPTS="-c opt --show_progress_rate_limit=10.0"
  -export BAZEL_VERSION=3.7.0
  +export BAZEL_VERSION=4.0.0
  # Without following environment variable set, Bazel updates itself to the
  # latest version
  export USE_BAZEL_VERSION=$BAZEL_VERSION
  