[6.4] Allow 7.0 deps

Author: nicolas-grekas

composer.json

@@ -20,15 +20,15 @@
         "symfony/deprecation-contracts": "^2.5|^3",
         "symfony/polyfill-mbstring": "~1.0",
         "symfony/service-contracts": "^2.5|^3",
-        "symfony/string": "^5.4|^6.0"
+        "symfony/string": "^5.4|^6.0|^7.0"
     },
     "require-dev": {
-        "symfony/config": "^5.4|^6.0",
-        "symfony/event-dispatcher": "^5.4|^6.0",
-        "symfony/dependency-injection": "^5.4|^6.0",
-        "symfony/lock": "^5.4|^6.0",
-        "symfony/process": "^5.4|^6.0",
-        "symfony/var-dumper": "^5.4|^6.0",
+        "symfony/config": "^5.4|^6.0|^7.0",
+        "symfony/event-dispatcher": "^5.4|^6.0|^7.0",
+        "symfony/dependency-injection": "^5.4|^6.0|^7.0",
+        "symfony/lock": "^5.4|^6.0|^7.0",
+        "symfony/process": "^5.4|^6.0|^7.0",
+        "symfony/var-dumper": "^5.4|^6.0|^7.0",
         "psr/log": "^1|^2|^3"
     },
     "provide": {