Update composer.json

Author: barryvdh

composer.json

@@ -12,7 +12,7 @@
     "require": {
         "php": ">=7",
         "illuminate/support": "5.5.x|5.6.x|5.7.x",
-        "symfony/form": "^3.4",
+        "symfony/form": "^3.4|^4",
         "symfony/validator": "^3|^4",
         "symfony/twig-bridge": "^3|^4",
         "twig/twig": "~1.30|~2.0"