update with existing .openpublishing.publish.config.json

Author: herohua

.openpublishing.publish.config.json

@@ -18,17 +18,18 @@
     }
   ],
   "notification_subscribers": [],
+  "sync_notification_subscribers": null,
   "branches_to_filter": [],
   "git_repository_url_open_to_public_contributors": "https://github.com/MicrosoftDocs/VBA-Docs",
-  "git_repository_branch_open_to_public_contributors": "master",
+  "git_repository_branch_open_to_public_contributors": "main",
   "skip_source_output_uploading": false,
   "need_preview_pull_request": true,
   "contribution_branch_mappings": {},
   "dependent_repositories": [
     {
       "path_to_root": "_themes",
       "url": "https://github.com/Microsoft/templates.docs.msft",
-      "branch": "master",
+      "branch": "main",
       "branch_mapping": {}
     }
   ],
@@ -38,4 +39,4 @@
   "docs_build_engine": {
     "name": "docfx_v3"
   }
-}
+}