Update copy-rules-to-wcag.yml

Copy rules to WCAG when they are merged to `publication` instead of `main`.

Author: remibetin

.github/workflows/copy-rules-to-wcag.yml

@@ -14,7 +14,7 @@ name: Copy-rules-to-WCAG
 on: 
   push:
     branches:
-      - main
+      - publication
     paths:
       - wcag-mapping.json