Update dependency typescript to v3.4.3 (#163)

Author: renovate-bot

package.json

@@ -47,7 +47,7 @@
     "rollup": "0.67.4",
     "rollup-plugin-copy": "1.1.0",
     "tslint": "5.13.0",
-    "typescript": "3.3.3333"
+    "typescript": "3.4.3"
   },
   "files": [
     "dist/index.d.ts",