Remove dependency on php-http/message-factory

Author: JoepdeJong

composer.json

@@ -20,7 +20,6 @@
         "php-http/client-common": "^2.0",
         "php-http/discovery": "^1.0",
         "php-http/httplug": "^2.0",
-        "php-http/message-factory": "^1.0",
         "psr/http-client": "^1.0",
         "psr/http-factory": "^1.0",
         "psr/http-message": "^1.0 || ^2.0",