chore(package): update istanbul to version 0.4.3

http://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -20,7 +20,7 @@
   },
   "devDependencies": {
     "expect": "1.14.0",
-    "istanbul": "0.4.1",
+    "istanbul": "0.4.3",
     "mocha": "2.4.4",
     "mocha-clean": "1.0.0",
     "mocha-standard": "1.0.0",