message: Update babylon parser to latest version, 7.0.0-beta.42.
diff: "devDependencies": {
  "@babel/core": "^7.0.0-beta.40",
  "@babel/preset-es2015": "^7.0.0-beta.40",
  - "babylon": "^7.0.0-beta.40",
  + "babylon": "^7.0.0-beta.42",
  "esprima-fb": "^15001.1001.0-dev-harmony-fb",
  "flow-parser": "^0.67.1",
  "glob": "^7.1.2",
  