chore(package): update ava to version 2.3.0

Closes #56

Author: greenkeeper[bot]

package.json

@@ -52,7 +52,7 @@
     "uuid": "^3.3.2"
   },
   "devDependencies": {
-    "ava": "^0.25.0",
+    "ava": "^2.3.0",
     "babel-cli": "^6.26.0",
     "babel-core": "^6.26.0",
     "babel-eslint": "^8.0.1",