initial COmmit: Add KB Antora Importer plugin files

kb-antora-importer/includes/GitLab/GitLabBranch.php

@@ -0,0 +1,13 @@
+<?php
+declare(strict_types=1);
+
+namespace KbAntoraImporter\GitLab;
+
+final class GitLabBranch
+{
+    public function __construct(
+        public readonly string $name,
+        public readonly string $commitSha = ''
+    ) {
+    }
+}