Merge pull request #4 from kitlabs-cn/master

update httplug version constraint

Author: Julien Neuhart

composer.json

@@ -25,7 +25,7 @@
     "php" : ">=7.1",
     "psr/http-message": "^1.0",
     "php-http/client-implementation": "^1.0",
-    "php-http/httplug": "^1.0",
+    "php-http/httplug": ">=1.0",
     "php-http/discovery": "^1.0",
     "guzzlehttp/psr7": "^1.4.2",
     "php-http/message": "^1.0",