Upgrade ui frontend semver dependencies

Some packages say they allow any version of `@types/react`, but that's
a lie. Constrain them for now.

Author: shepmaster

ui/frontend/package.json

@@ -3,6 +3,9 @@
   "version": "0.0.1",
   "description": "UI for the Rust playground",
   "main": "index.js",
+  "resolutions": {
+    "@types/react": "^17.0.2"
+  },
   "dependencies": {
     "@popperjs/core": "^2.4.0",
     "ace-builds": "^1.4.4",