Merge pull request #528 from acrobat/integration-authentication-doc-fix

Fixed integration authentication example

Author: Nyholm

doc/security.md

@@ -54,14 +54,18 @@ The following sample code authenticates as an installation using [lcobucci/jwt](
 to generate a JSON Web Token (JWT).
 
 ```php
+use Lcobucci\JWT\Builder;
+use Lcobucci\JWT\Signer\Key;
+use Lcobucci\JWT\Signer\Rsa\Sha256;
+
 $builder = new Github\HttpClient\Builder(new GuzzleClient());
 $github = new Github\Client($builder, 'machine-man-preview');
 
 $jwt = (new Builder)
     ->setIssuer($integrationId)
     ->setIssuedAt(time())
     ->setExpiration(time() + 60)
-    ->sign(new Sha256(),  (new Keychain)->getPrivateKey($pemPrivateKeyPath))
+    ->sign(new Sha256(),  new Key('file:///path/to/integration.private-key.pem'))
     ->getToken();
 
 $github->authenticate($jwt, null, Github\Client::AUTH_JWT);