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

Author: renovate-bot

Diff for: package.json

@@ -79,7 +79,7 @@
     "react": "16.13.1",
     "react-async": "10.0.0-alpha.0",
     "react-dom": "16.13.1",
-    "typescript": "3.8.3"
+    "typescript": "3.9.9"
   },
   "resolutions": {
     "@types/react": "16.9.13"