fix(ci): preserve custom domain during deployment

Author: o6-nbeier

.github/workflows/deploy-gh-pages.yml

@@ -58,4 +58,5 @@ jobs:
           publish_branch: gh-pages-new
           force_orphan: false
           keep_files: false
+          cname: open62541.org
           commit_message: 'Deploy from ${{ github.sha }}'