update with existing .openpublishing.publish.config.json

Author: herohua

.openpublishing.publish.config.json

@@ -21,21 +21,21 @@
   "sync_notification_subscribers": [],
   "branches_to_filter": [],
   "git_repository_url_open_to_public_contributors": "https://github.com/MicrosoftDocs/office-developer-client-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": false,
   "contribution_branch_mappings": {},
   "dependent_repositories": [
     {
       "path_to_root": "_themes",
       "url": "https://github.com/Microsoft/templates.docs.msft",
-      "branch": "master",
+      "branch": "main",
       "branch_mapping": {}
     },
     {
       "path_to_root": "_themes.pdf",
       "url": "https://github.com/Microsoft/templates.docs.msft.pdf",
-      "branch": "master",
+      "branch": "main",
       "branch_mapping": {}
     }
   ],
@@ -44,7 +44,7 @@
       "Publish",
       "Pdf"
     ],
-    "master": [
+    "main": [
       "Publish",
       "Pdf"
     ]
@@ -58,4 +58,4 @@
   "docs_build_engine": {
     "name": "docfx_v3"
   }
-}
+}