chore(package): update ava to version 1.2.0

Closes #74

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
     "rucksack-css": "^1.0.2"
   },
   "devDependencies": {
-    "ava": "^0.25.0",
+    "ava": "^1.2.0",
     "coveralls": "^3.0.0",
     "nyc": "13.1.0",
     "rewire": "^4.0.1",