Add RuboCop 1.73

Author: bbatsov

antora-playbook.yml

@@ -1,7 +1,7 @@
 site:
   title: RuboCop Docs
   url: https://docs.rubocop.org/
-  start_page: 1.72@rubocop::index.adoc
+  start_page: 1.73@rubocop::index.adoc
   keys:
     google_analytics: "UA-140153536-1"
 urls:
@@ -26,6 +26,7 @@ content:
           "v1.70.0",
           "v1.71.0",
           "v1.72.2",
+          "v1.73.0",
         ]
       start_path: docs
     - url: https://github.com/rubocop/rubocop-ast.git