Bump the npm_and_yarn group across 2 directories with 3 updates

Bumps the npm_and_yarn group with 2 updates in the / directory: [postcss](https://github.com/postcss/postcss) and [vite](https://github.com/vitejs/vite/tree/HEAD/packages/vite).
Bumps the npm_and_yarn group with 1 update in the /backend directory: [express](https://github.com/expressjs/express).


Updates `postcss` from 8.4.8 to 8.4.31
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.4.8...8.4.31)

Updates `vite` from 5.0.0 to 5.4.19
- [Release notes](https://github.com/vitejs/vite/releases)
- [Changelog](https://github.com/vitejs/vite/blob/v5.4.19/packages/vite/CHANGELOG.md)
- [Commits](https://github.com/vitejs/vite/commits/v5.4.19/packages/vite)

Updates `express` from 4.16.4 to 5.1.0
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](expressjs/express@4.16.4...v5.1.0)

---
updated-dependencies:
- dependency-name: postcss
  dependency-version: 8.4.31
  dependency-type: direct:development
  dependency-group: npm_and_yarn
- dependency-name: vite
  dependency-version: 5.4.19
  dependency-type: direct:development
  dependency-group: npm_and_yarn
- dependency-name: express
  dependency-version: 5.1.0
  dependency-type: direct:production
  dependency-group: npm_and_yarn
...

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

Author: dependabot[bot]

backend/package.json

@@ -8,7 +8,7 @@
   "dependencies": {
     "cookie-parser": "~1.4.4",
     "debug": "~2.6.9",
-    "express": "~4.16.1",
+    "express": "~5.1.0",
     "mongoose": "^8.16.2",
     "morgan": "~1.9.1",
     "nodemailer": "^7.0.5",

package.json

@@ -61,9 +61,9 @@
     "@tailwindcss/typography": "^0.5.16",
     "@vitejs/plugin-react": "4.3.4",
     "autoprefixer": "10.4.2",
-    "postcss": "8.4.8",
+    "postcss": "8.4.31",
     "tailwindcss": "3.4.6",
-    "vite": "5.0.0",
+    "vite": "5.4.19",
     "vite-tsconfig-paths": "3.6.0"
   }
 }