Allow v3 contracts where possible

Author: derrabus

composer.json

@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": ">=7.2.5",
-        "symfony/deprecation-contracts": "^2.1",
+        "symfony/deprecation-contracts": "^2.1|^3",
         "symfony/polyfill-ctype": "~1.8",
         "symfony/polyfill-mbstring": "~1.0",
         "symfony/polyfill-php80": "^1.16"