fix: playground/react/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-HTTPPROXYMIDDLEWARE-8229906
- https://snyk.io/vuln/SNYK-JS-SERIALIZEJAVASCRIPT-6147607

playground/react/package.json

@@ -48,12 +48,12 @@
     "sass-loader": "8.0.2",
     "semver": "6.3.0",
     "style-loader": "0.23.1",
-    "terser-webpack-plugin": "2.3.5",
+    "terser-webpack-plugin": "5.3.11",
     "ts-pnp": "1.1.6",
     "typescript": "^3.9.2",
     "url-loader": "2.3.0",
     "webpack": "4.42.0",
-    "webpack-dev-server": "3.10.3",
+    "webpack-dev-server": "5.2.0",
     "webpack-manifest-plugin": "2.2.0",
     "workbox-webpack-plugin": "4.3.1"
   },