[Contracts] add return types and bump to v3

Author: nicolas-grekas

composer.json

@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": ">=8.0.2",
-        "symfony/deprecation-contracts": "^2.1"
+        "symfony/deprecation-contracts": "^2.1|^3.0"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\OptionsResolver\\": "" },