chore(package): update ava to version 3.6.0

Closes #45

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
   },
   "homepage": "https://github.com/hhsnopek/code-frame#readme",
   "devDependencies": {
-    "ava": "^0.25.0",
+    "ava": "^3.6.0",
     "coveralls": "^3.0.0",
     "nyc": "^11.0.0",
     "snazzy": "^7.1.1",