Updated docs

Author: Nyholm

doc/api_version.md

@@ -8,6 +8,6 @@ For example:
 $client = new Github\Client();
 echo $client->getApiVersion(); // prints "v3"
 
-$client = new Github\Client($httpClient, 'v2');
+$client = new Github\Client(new Github\HttpClient\Builder(), 'v2');
 echo $client->getApiVersion(); // prints "v2"
 ```

doc/security.md

@@ -54,7 +54,7 @@ The following sample code authenticates as an installation using [lcobucci/jwt](
 to generate a JSON Web Token (JWT).
 
 ```php
-$github = new Github\Client(new GuzzleClient(), 'machine-man-preview');
+$github = new Github\Client(new Github\HttpClient\Builder(), 'machine-man-preview');
 
 $jwt = (new Builder)
     ->setIssuer($integrationId)