chore(package): update ava to version 1.4.0

Closes #31

Author: greenkeeper[bot]

package.json

@@ -28,7 +28,7 @@
     "browser"
   ],
   "devDependencies": {
-    "ava": "^0.19.0",
+    "ava": "^1.4.0",
     "babel-cli": "^6.24.0",
     "babel-plugin-add-module-exports": "^0.2.1",
     "babel-preset-env": "^1.3.2",