chore(package): update ava to version 2.3.0

Closes #73

Author: greenkeeper[bot]

package.json

@@ -28,7 +28,7 @@
     "promise.prototype.finally": "2.0.1"
   },
   "devDependencies": {
-    "ava": "^0.25.0",
+    "ava": "^2.3.0",
     "coveralls": "^3.0.1",
     "eslint": "^4.19.1",
     "eslint-config-pedant": "^1.0.0",