chore(package): update ava to version 3.1.0

Closes #24

Author: greenkeeper[bot]

package.json

@@ -57,7 +57,7 @@
   },
   "devDependencies": {
     "@types/node": "^10.12.0",
-    "ava": "^0.25.0",
+    "ava": "^3.1.0",
     "codecov": "^3.1.0",
     "concurrently": "^4.0.1",
     "cpx": "^1.5.0",