Bump babel-related deps (facebook#4159)

* Add explicit dep on plugin-proposal-object-rest-spread to babel-preset-react-app

* Bump babel-related deps to beta.42

* Pass useBuiltIns directly to react-preset

package.json

@@ -21,11 +21,11 @@
     "react-scripts": "./bin/react-scripts.js"
   },
   "dependencies": {
-    "@babel/core": "7.0.0-beta.38",
-    "@babel/runtime": "7.0.0-beta.38",
+    "@babel/core": "7.0.0-beta.42",
+    "@babel/runtime": "7.0.0-beta.42",
     "autoprefixer": "7.2.5",
     "babel-core": "7.0.0-bridge.0",
-    "babel-eslint": "8.2.1",
+    "babel-eslint": "8.2.2",
     "babel-jest": "22.1.0",
     "babel-loader": "8.0.0-beta.0",
     "babel-plugin-named-asset-import": "^0.1.0",