fix: package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-WS-1296835

package.json

@@ -26,7 +26,7 @@
     "react-hot-loader": "^4.3.4",
     "react-jazzicon": "^0.1.3",
     "react-linkify": "^0.2.2",
-    "react-scripts": "2.1.3",
+    "react-scripts": "4.0.0",
     "react-spinners": "^0.4.7",
     "react-spotify-player": "^1.0.4",
     "react-syntax-highlighter": "^10.0.1",