add forks API call to return all forked projects

Author: pkolmann

lib/Gitlab/Api/Projects.php

@@ -650,6 +650,18 @@ public function languages($project_id)
         return $this->get($this->getProjectPath($project_id, 'languages'));
     }
 
+    /**
+     * @param int $project_id
+     * @param array $parameters
+     * @return mixed
+     */
+    public function forks($project_id, array $parameters = [])
+    {
+        $resolver = $this->createOptionsResolver();
+
+        return $this->get($this->getProjectPath($project_id, 'forks'), $resolver->resolve($parameters));
+    }
+
     /**
      * @param int $project_id
      * @param array $params (