Update dependency ava-ts to v0.25.2

Author: renovate-bot

package.json

@@ -82,7 +82,7 @@
   "devDependencies": {
     "@types/node": "^8.0.47",
     "ava": "^0.23.0",
-    "ava-ts": "0.23.0",
+    "ava-ts": "0.25.2",
     "concurrently": "^3.5.0",
     "custom-tslint-formatters": "^2.1.1",
     "nodemon": "1.12.1",