chore(package): update babel-istanbul to version 0.4.0

http://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -40,7 +40,7 @@
   "devDependencies": {
     "babel": "^5.4.7",
     "babel-eslint": "^4.1.3",
-    "babel-istanbul": "^0.3.20",
+    "babel-istanbul": "^0.4.0",
     "babelify": "^6.1.2",
     "chokidar-cli": "^1.0.1",
     "codecov.io": "^0.1.2",