Bump dependencies

composer.json

@@ -28,9 +28,9 @@
     "php": ">=7.1",
     "contao/core-bundle": "^4.9",
     "paragonie/hidden-string": "^1.0",
-    "symfony/config": "^4.0",
-    "symfony/dependency-injection": "^4.0",
-    "symfony/http-kernel": "^4.0"
+    "symfony/config": "^4.0 || ^5.0",
+    "symfony/dependency-injection": "^4.0 || ^5.0",
+    "symfony/http-kernel": "^4.0 || ^5.0"
   },
   "require-dev": {
     "contao/manager-plugin": "^2.7",