Update symfony/flex requirement from ^1.3.1 to ^2.4.0

Updates the requirements on [symfony/flex](https://github.com/symfony/flex) to permit the latest version.
- [Release notes](https://github.com/symfony/flex/releases)
- [Commits](symfony/flex@v1.3.1...v2.4.0)

---
updated-dependencies:
- dependency-name: symfony/flex
  dependency-type: direct:production
...

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

composer.json

@@ -39,7 +39,7 @@
     "symfony/messenger": "^5.4",
     "symfony/doctrine-messenger": "^5.4",
     "symfony/filesystem": "^5.4",
-    "symfony/flex": "^1.3.1",
+    "symfony/flex": "^2.4.0",
     "symfony/form": "^5.4",
     "symfony/framework-bundle": "^5.4",
     "symfony/mime": "^5.4",