Merge pull request #3 from GrahamCampbell/patch-1

Update composer.json

Author: mtdowling

composer.json

@@ -13,7 +13,7 @@
     ],
     "require": {
         "php": ">=5.4.0",
-        "guzzlehttp/guzzle": "4.0.*@RC"
+        "guzzlehttp/guzzle": "~4.0"
     },
     "autoload": {
         "psr-4": { "GuzzleHttp\\Subscriber\\Cache\\": "src" }