chore(package): update ava to version 0.17.0 (#229)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -39,7 +39,7 @@
     "@types/diff": "0.0.31",
     "@types/node": "6.0.46",
     "@types/react": "0.14.44",
-    "ava": "0.16.0",
+    "ava": "0.17.0",
     "babel-core": "6.18.2",
     "babel-preset-es2015": "6.18.0",
     "babel-register": "6.18.0",