Improve composer.json

Author: sagikazarmark

composer.json

@@ -11,7 +11,7 @@
         }
     ],
     "require": {
-        "php": ">=5.4",
+        "php": "^5.4 || ^7.0",
         "psr/cache": "^1.0",
         "php-http/client-common": "^1.1",
         "php-http/message-factory": "^1.0",
@@ -39,7 +39,5 @@
         "branch-alias": {
             "dev-master": "1.1-dev"
         }
-    },
-    "prefer-stable": true,
-    "minimum-stability": "dev"
+    }
 }