Update dependency tslint to v5.15.0

Author: renovate-bot

package-lock.json

@@ -90,7 +90,7 @@
     "rxjs": "6.4.0",
     "ts-node": "7.0.1",
     "tsickle": "0.34.3",
-    "tslint": "5.12.1",
+    "tslint": "5.15.0",
     "typescript": "3.2.4",
     "uuid": "3.3.2",
     "webpack-cli": "3.2.3",