Boolean private needed to create private repo as seen in: https://docs.github.com/en/rest/reference/repos#create-an-organization-repository

Author: Marvin Alexander Rüll

lib/Github/Api/Repo.php

@@ -205,6 +205,7 @@ public function create(
             'name'          => $name,
             'description'   => $description,
             'homepage'      => $homepage,
+            'private'       => ($visibility ?? ($public ? 'public' : 'private')) === 'private',
             'visibility'    => $visibility ?? ($public ? 'public' : 'private'),
             'has_issues'    => $hasIssues,
             'has_wiki'      => $hasWiki,