Update dependency ava to v0.25.0 (#11)

Author: renovate[bot]

package.json

@@ -28,7 +28,7 @@
     "@aureooms/js-itertools": "^3.1.1"
   },
   "devDependencies": {
-    "ava": "0.19.1",
+    "ava": "0.25.0",
     "babel-cli": "6.26.0",
     "babel-polyfill": "6.26.0",
     "babel-preset-latest": "6.24.1",