revert allowing Twig 4

As Twig 4 will not be released before Symfony 7.2 we should not claim
compatibility before a stable Twig 4 release.

Author: xabbuh

composer.json

@@ -23,7 +23,7 @@
         "symfony/twig-bridge": "^6.4|^7.0",
         "symfony/http-foundation": "^6.4|^7.0",
         "symfony/http-kernel": "^6.4|^7.0",
-        "twig/twig": "^3.12|^4.0"
+        "twig/twig": "^3.12"
     },
     "require-dev": {
         "symfony/asset": "^6.4|^7.0",