chore(package): update ava to version 1.4.0

Closes #19

Author: greenkeeper[bot]

package.json

@@ -41,7 +41,7 @@
     "micro": "^9.0.0"
   },
   "devDependencies": {
-    "ava": "^0.25.0",
+    "ava": "^1.4.0",
     "coveralls": "^3.0.0",
     "eslint-config-xo-lukechilds": "^1.0.0",
     "nyc": "^11.0.3",