Allow Symfony ^8.0

Author: nicolas-grekas

composer.json

@@ -20,9 +20,9 @@
         "symfony/deprecation-contracts": "^2.5|^3"
     },
     "require-dev": {
-        "symfony/property-access": "^6.4|^7.0",
-        "symfony/serializer": "^6.4|^7.0",
-        "symfony/var-dumper": "^6.4|^7.0"
+        "symfony/property-access": "^6.4|^7.0|^8.0",
+        "symfony/serializer": "^6.4|^7.0|^8.0",
+        "symfony/var-dumper": "^6.4|^7.0|^8.0"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\VarExporter\\": "" },