N°8017 - Security - dependabot - Symfony's VarDumper vulnerable to un… (#731)

Upgrade all Symfony components to last security fix (~6.4.0)

lib/symfony/polyfill-mbstring/composer.json

@@ -16,7 +16,8 @@
         }
     ],
     "require": {
-        "php": ">=7.1"
+        "php": ">=7.2",
+        "ext-iconv": "*"
     },
     "provide": {
         "ext-mbstring": "*"
@@ -30,9 +31,6 @@
     },
     "minimum-stability": "dev",
     "extra": {
-        "branch-alias": {
-            "dev-main": "1.28-dev"
-        },
         "thanks": {
             "name": "symfony/polyfill",
             "url": "https://github.com/symfony/polyfill"