fix: client.sh breaks with ts > 4.05

facebook/create-react-app#10110

Author: gvinokur

js/doc-landing/package.json

@@ -14,7 +14,7 @@
     "react": "^17.0.1",
     "react-dom": "^17.0.1",
     "react-scripts": "4.0.0",
-    "typescript": "^4.0.5",
+    "typescript": "~4.0.5",
     "web-vitals": "^0.2.4"
   },
   "scripts": {