feat: upgrade typescript to 3.1.6

Author: oriondean

package-lock.json

@@ -26,7 +26,7 @@
     "rimraf": "^2.6.1",
     "selenium-webdriver": "^3.4.0",
     "semantic-release": "^6.3.6",
-    "typescript": "^2.9.2",
+    "typescript": "^3.1.6",
     "uglify-js": "^3.0.24",
     "webdriver-manager": "^12.0.6"
   },