Update .openpublishing.publish.config.json

.openpublishing.publish.config.json

@@ -119,7 +119,7 @@
       }
     },
     {
-      "TopLevelTOC": "docs-ref-mapping/reference.yml",
+      "TopLevelTOC": "preview/docs-ref-mapping/reference.yml",
       "ReferenceTOC": "preview/docs-ref-autogen/toc.yml",
       "ConceptualTOC": "docs-ref-conceptual/toc.yml",
       "ReferenceTOCUrl": "/java/api/azure-java-sdk/toc.json?view=azure-java-preview",