Bump express from 4.19.2 to 4.21.0

Bumps [express](https://github.com/expressjs/express) from 4.19.2 to 4.21.0.
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/4.21.0/History.md)
- [Commits](expressjs/express@4.19.2...4.21.0)

---
updated-dependencies:
- dependency-name: express
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -71,7 +71,7 @@
     "@vuepress/theme-default": "^2.0.0-rc.37",
     "compression": "^1.7.4",
     "cross-env": "^7.0.3",
-    "express": "^4.19.2",
+    "express": "^4.21.0",
     "pinia": "^2.1.7",
     "pinia-plugin-persistedstate": "^3.2.1",
     "sass": "^1.77.6",