chore(package): update typescript to version 2.1.5

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -7,6 +7,6 @@
   "devDependencies": {
     "codelyzer": "0.0.28",
     "tslint": "^4.3.1",
-    "typescript": "2.0.8"
+    "typescript": "2.1.5"
   }
 }