Require http-adapter ~0.8

Fix #438
Fix #442
Fix #443

Author: willdurand

composer.json

@@ -13,7 +13,7 @@
     ],
     "require": {
         "php": ">=5.4.0",
-        "egeloen/http-adapter": "~0.7",
+        "egeloen/http-adapter": "~0.8",
         "igorw/get-in": "~1.0"
     },
     "require-dev": {