Bump dayjs from 1.11.18 to 1.11.20 in /frontend

Bumps [dayjs](https://github.com/iamkun/dayjs) from 1.11.18 to 1.11.20.
- [Release notes](https://github.com/iamkun/dayjs/releases)
- [Changelog](https://github.com/iamkun/dayjs/blob/dev/CHANGELOG.md)
- [Commits](iamkun/dayjs@v1.11.18...v1.11.20)

---
updated-dependencies:
- dependency-name: dayjs
  dependency-version: 1.11.20
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

frontend/package.json

@@ -62,7 +62,7 @@
     "compression": "^1.7.4",
     "cookie-parser": "^1.4.6",
     "cross-env": "^7.0.3",
-    "dayjs": "^1.11.8",
+    "dayjs": "^1.11.20",
     "dotenv": "^16.4.7",
     "express": "^4.19.2",
     "qr-scanner": "^1.4.2",