Update dependency tslint to v6

Author: renovate-bot

package.json

@@ -33,7 +33,7 @@
   },
   "devDependencies": {
     "typescript": "~3.1.1",
-    "tslint": "^5.11.0",
+    "tslint": "^6.0.0",
     "tslint-config-standard": "^8.0.1",
     "static-type-assert": "^3.0.0",
     "toolcheck": "^0.0.5",