fix: upgrade react-router from 5.3.3 to 5.3.4

Snyk has created this PR to upgrade react-router from 5.3.3 to 5.3.4.

See this package in npm:
https://www.npmjs.com/package/react-router

See this project in Snyk:
https://app.snyk.io/org/nexuscompute/project/3295247b-14f9-44b5-84b4-8f5b949cc907?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot

demo/package.json

@@ -36,7 +36,7 @@
     "preact-render-to-string": "^5.0.2",
     "preact-router": "^3.0.0",
     "react-redux": "^7.1.0",
-    "react-router": "^5.0.1",
+    "react-router": "^5.3.4",
     "react-router-dom": "^5.0.1",
     "redux": "^4.0.1",
     "styled-components": "^4.2.0"