Fixes incorrect namespace for ConfigProvider

The `composer.json` had an incorrect namespace for the `ConfigProvider`,
which meant that once injected into a `config.php` file, an error would
immediately occur. This patch fixes that situation.

Author: weierophinney

composer.json

@@ -58,7 +58,7 @@
             "dev-master": "1.0-dev"
         },
         "zf": {
-            "config-provider": "Phly\\OAuth2ClientAuthentication\\ConfigProvider"
+            "config-provider": "Phly\\Expressive\\OAuth2ClientAuthentication\\ConfigProvider"
         }
     },
     "scripts": {