Update dependency typescript to v3.4.2

Author: renovate-bot

package-lock.json

@@ -54,7 +54,7 @@
     "tslint-config-prettier": "1.18.0",
     "tslint-eslint-rules": "5.4.0",
     "tslint-plugin-prettier": "2.0.1",
-    "typescript": "3.4.1"
+    "typescript": "3.4.2"
   },
   "dependencies": {
     "pdfobject": "^2.1.1"