chore(package): update ava to version 3.2.0

Closes #16

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "ms": "^2.0.0"
   },
   "devDependencies": {
-    "ava": "^1.0.1",
+    "ava": "^3.2.0",
     "babel-cli": "^6.24.1",
     "babel-core": "^6.26.3",
     "babel-eslint": "^10.0.1",