Allow "psr/http-message" v2

Author: nicolas-grekas

composer.json

@@ -17,7 +17,7 @@
         "php-http/message-factory": "^1.0",
         "psr/http-client": "^1.0",
         "psr/http-factory": "^1.0",
-        "psr/http-message": "^1.0",
+        "psr/http-message": "^1.0 || ^2.0",
         "symfony/options-resolver": "~4.0.15 || ~4.1.9 || ^4.2.1 || ^5.0 || ^6.0",
         "symfony/polyfill-php80": "^1.17"
     },