Update dependency typescript to v3.4.4

Author: renovate-bot

package-lock.json

@@ -40,7 +40,7 @@
     "tslint": "^5.11.0",
     "tslint-consistent-codestyle": "^1.13.3",
     "ttypescript": "^1.5.5",
-    "typescript": "3.4.0-dev.20190227"
+    "typescript": "3.4.4"
   },
   "peerDependencies": {
     "typescript": "*"