chore(package): update ava to version 1.2.0

Closes #33

Author: greenkeeper[bot]

package.json

@@ -20,7 +20,7 @@
     "when": "^3.7.8"
   },
   "devDependencies": {
-    "ava": "^0.24.0",
+    "ava": "^1.2.0",
     "coveralls": "^3.0.0",
     "nyc": "^11.3.0",
     "prettier": "^1.9.0",