Added checks() in Repo. (#809)

* added checks() in Repo

* tidy

* removed space at end of line

* removed another space at end of line

* moved use-statement

lib/Github/Api/Repo.php

@@ -311,6 +311,18 @@ public function commits()
         return new Commits($this->client);
     }
 
+    /**
+     * Manage checks on a repository.
+     *
+     * @link https://developer.github.com/v3/checks/
+     *
+     * @return Checks
+     */
+    public function checks()
+    {
+        return new Checks($this->client);
+    }
+
     /**
      * Manage the content of a repository.
      *