Bump Symfony 6 to PHP 8

Author: nicolas-grekas

composer.json

@@ -16,12 +16,11 @@
         }
     ],
     "require": {
-        "php": ">=7.2.5",
+        "php": ">=8.0.2",
         "symfony/polyfill-ctype": "~1.8",
         "symfony/polyfill-intl-grapheme": "~1.0",
         "symfony/polyfill-intl-normalizer": "~1.0",
-        "symfony/polyfill-mbstring": "~1.0",
-        "symfony/polyfill-php80": "~1.15"
+        "symfony/polyfill-mbstring": "~1.0"
     },
     "require-dev": {
         "symfony/error-handler": "^4.4|^5.0",