npm-dep: bump autoprefixer from 10.4.14 to 10.4.15 in /frontend

Bumps [autoprefixer](https://github.com/postcss/autoprefixer) from 10.4.14 to 10.4.15.
- [Release notes](https://github.com/postcss/autoprefixer/releases)
- [Changelog](https://github.com/postcss/autoprefixer/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/autoprefixer/compare/10.4.14...10.4.15)

---
updated-dependencies:
- dependency-name: autoprefixer
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

frontend/package.json

@@ -17,7 +17,7 @@
 		"@sveltejs/kit": "^1.22.5",
 		"@typescript-eslint/eslint-plugin": "^6.3.0",
 		"@typescript-eslint/parser": "^6.3.0",
-		"autoprefixer": "^10.4.14",
+		"autoprefixer": "^10.4.15",
 		"daisyui": "^3.5.1",
 		"eslint": "^8.47.0",
 		"eslint-config-prettier": "^9.0.0",