chore(deps): update dependency typescript to v3.9.9

Author: renovate-bot

package-lock.json

@@ -63,7 +63,7 @@
     "tslint": "5.20.1",
     "tslint-config-prettier": "1.18.0",
     "tslint-config-standard": "8.0.1",
-    "typescript": "3.9.7"
+    "typescript": "3.9.9"
   },
   "eslintConfig": {
     "extends": [