Use the official syntax [skip CI]

Author: Jean85

composer.json

@@ -12,7 +12,7 @@
     ],
     "require": {
         "php": "^5.4 || ^7.0",
-        "php-http/httplug": "^1.1|^2.0",
+        "php-http/httplug": "^1.1 || ^2.0",
         "php-http/message-factory": "^1.0",
         "php-http/message": "^1.6",
         "symfony/options-resolver": "^2.6 || ^3.0 || ^4.0"