chore(package): update ava to version 0.18.0

https://greenkeeper.io/

Author: greenkeeper[bot]

package.json

@@ -30,7 +30,7 @@
     "aureooms-js-mem": "^1.0.2",
     "aureooms-js-operator": "^1.0.2",
     "aureooms-js-type": "^1.0.4",
-    "ava": "^0.17.0",
+    "ava": "^0.18.0",
     "babel-cli": "^6.22.2",
     "babel-polyfill": "^6.22.0",
     "babel-preset-env": "^1.1.8",