[Mime] Deprecate implementing __sleep/wakeup() on AbstractPart implementations

Author: nicolas-grekas

composer.json

@@ -23,7 +23,7 @@
         "php": ">=8.1.0"
     },
     "require-dev": {
-        "symfony/deprecation-contracts": "^2.5|^3.0",
+        "symfony/deprecation-contracts": "^2.5|^3",
         "symfony/error-handler": "^6.4.3|^7.0.3|^8.0"
     },
     "autoload": {