chore(deps): bump path-to-regexp and express in /backend

Bumps [path-to-regexp](https://github.com/pillarjs/path-to-regexp) to 0.1.12 and updates ancestor dependency [express](https://github.com/expressjs/express). These dependencies need to be updated together.


Updates `path-to-regexp` from 0.1.10 to 0.1.12
- [Release notes](https://github.com/pillarjs/path-to-regexp/releases)
- [Changelog](https://github.com/pillarjs/path-to-regexp/blob/master/History.md)
- [Commits](pillarjs/path-to-regexp@v0.1.10...v0.1.12)

Updates `express` from 4.21.0 to 4.21.2
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/4.21.2/History.md)
- [Commits](expressjs/express@4.21.0...4.21.2)

---
updated-dependencies:
- dependency-name: path-to-regexp
  dependency-type: indirect
- dependency-name: express
  dependency-type: direct:production
...

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

backend/package.json

@@ -16,7 +16,7 @@
     "@babel/runtime": "^7.13.10",
     "compression": "^1.7.4",
     "cors": "^2.8.5",
-    "express": "^4.21.0",
+    "express": "^4.21.2",
     "https": "^1.0.0",
     "jose": "^5.2.4",
     "js-yaml": "^4.1.0",